Soft X-ray Imaging Research Articles

Target Strength and swimbladder morphology of Mueller\u2019s pearlside (Maurolicus muelleri)

In the last few years, there has been increasing interest in the commercial exploitation of mesopelagic fish and a trawl-acoustic methodology has been recommended to make estimates of abundance of these resources. This study provides relevant information on the scattering properties of a key mesopelagic fish species in the Bay of Biscay, Mueller’s pearlside (Maurolicus muelleri), necessary to convert the acoustic density into numerical abundance. The target strength (TS) of pearlside was estimated for the first time at five frequencies commonly used in acoustic surveys. A high-density filter was applied to reduce the bias derived from overlapping echoes erroneously assigned to single targets. Its relationship with fish length (b20) was also determined (−65.9 ± 2, −69.2 ± 3, −69.2 ± 2, −69.5 ± 2.5 and −71.5 ± 2.5 dB at 18, 38, 70, 120 and 200 kHz, respectively). Biomass estimates of pearlside in the Bay of Biscay during the four years of study (2014–2017) are given using the 38 kHz frequency. Morphological measurements of the swimbladder were obtained from soft X-ray images and used in the backscattering simulation of a gas-filled ellipsoid. Pearlside is a physoclist species, which means that they can compensate the swimbadder volume against pressure changes. However, the best fit between the model and the experimental data showed that they lose that capacity during the trawling process, when the swimbladder volume is affected by Boyle’s law.

Velocity map imaging of inelastic and elastic low energy electron scattering in organic nanoparticles.

Electron transport is of fundamental importance and has application in a variety of fields. Different scattering mechanisms affect electron transport in the condensed phase; hence, it is important to comprehensively understand these mechanisms and their scattering cross sections to predict electron transport properties. Whereas electron transport is well understood for high kinetic energy (KE) electrons, there is a discrepancy in the experimental and theoretical values for the Inelastic Mean Free Path (IMFP) in the low KE regime. In this work, velocity map imaging soft X-ray photoelectron spectroscopy is applied to unsupported organic nanoparticles (squalene) to extract experimental values of inelastic and elastic mean free paths (EMFPs). The obtained data are used to calculate corresponding scattering cross sections. The data demonstrate a decrease in the IMFP and increase in the EMFP with increasing electron KE between 10 and 50 eV.

Demonstration of soft X-ray 3D scanning and modeling with a glass gas electron multiplier

A new detector, based on an optical-readout glass gas electron multiplier was developed for a soft X-ray CT scanner. Soft X-ray imaging (<20 keV) provides high-contrast images of low-Z elements, such as soft tissues. We model a three-dimensional (3D) copy of a low-Z object with a high-resolution gaseous detector and a 3D printer. The detector was used to acquire high-resolution images to reconstruct a 3D computed tomography (CT) image. As an example, a fine 3D X-ray CT image of a hornet was reconstructed with high contrast. The 3D CT data were converted into 3D computer-automated design data, and a copy of the scanned object was printed with a commercial 3D printer. Overall, this work demonstrates a new use of gaseous detectors, rapid and precise soft X-ray 3D scanning, and modeling of soft tissues.

Quantitative Microscopy Reveals Stepwise Alteration of Chromatin Structure during Herpesvirus Infection.

During lytic herpes simplex virus 1 (HSV-1) infection, the expansion of the viral replication compartments leads to an enrichment of the host chromatin in the peripheral nucleoplasm. We have shown previously that HSV-1 infection induces the formation of channels through the compacted peripheral chromatin. Here, we used three-dimensional confocal and expansion microscopy, soft X-ray tomography, electron microscopy, and random walk simulations to analyze the kinetics of host chromatin redistribution and capsid localization relative to their egress site at the nuclear envelope. Our data demonstrated a gradual increase in chromatin marginalization, and the kinetics of chromatin smoothening around the viral replication compartments correlated with their expansion. We also observed a gradual transfer of capsids to the nuclear envelope. Later in the infection, random walk modeling indicated a gradually faster transport of capsids to the nuclear envelope that correlated with an increase in the interchromatin channels in the nuclear periphery. Our study reveals a stepwise and time-dependent mechanism of herpesvirus nuclear egress, in which progeny viral capsids approach the egress sites at the nuclear envelope via interchromatin spaces.

Emerging X-ray imaging technologies for energy materials

With the growing need for sustainable energy technologies, advanced characterization methods become more and more critical for optimizing energy materials and understanding their operation mechanisms. In this review, we focus on the synchrotron-based X-ray imaging technologies and the associated applications in gaining fundamental insights into the physical/chemical properties and reaction mechanisms of energy materials. We will discuss a few major X-ray imaging technologies, including X-ray projection imaging, transmission X-ray microscopy, scanning transmission X-ray microscopy, tender and soft X-ray imaging, and coherent diffraction imaging. Researchers can choose from various X-ray imaging techniques with different working principles based on research goals and sample specifications. With the X-ray imaging techniques, we can obtain the morphology, phase, lattice and strain information of energy materials in both 2D and 3D in an intuitive way. In addition, with the high-penetration X-rays and the high-brilliance synchrotron sources, operando/in-situ experiments can be designed to track the qualitative and quantitative changes of the samples during operation. We expect this review can broaden readers’ view on X-ray imaging techniques and inspire new ideas and possibilities in energy materials research.

Preliminary geometric parameters optimization of lobster-eye-type wide field of view soft x-ray imager

The lobster-eye optical system is widely used in the wide field of view (FOV) soft x-ray imaging device. The payload soft x-ray imager (SXI) onboard the solar wind magnetosphere ionosphere link explorer satellite will apply this technology to achieve panoramic imaging of the dayside magnetosphere. In order to optimize the imaging performance of SXI, we focus on geometric parameters optimization of a lobster-eye lens. The results show an appropriate microchannel ratio of length to width of lobster-eye optics with radius of curvature of 600 mm could be 30:1 (microchannel width of 40 μm and length of 1.2 mm). For a monochromatic parallel light source with energy of 1 keV, this combination of parameters can theoretically provide relatively large total effective area of about 15.52 cm2 and focusing efficiency of about 0.2887 along with spatial angular resolution of about 6 arc min at the center of FOV. Combined with the actual lobster-eye optics, the aberrations from deformation of the microchannel, the deviation of radius of curvature and planar detector are analyzed. For SXI with planar CCD detector, an optimum focal length could be 304.2 mm to ensure better resolution in full FOV.

Fast Tangentially Viewed Soft X-Ray Imaging System Based on Image Intensifier with Microchannel Plate Detector on QUEST

Fast Tangentially Viewed Soft X-Ray Imaging System Based on Image Intensifier with Microchannel Plate Detector on QUEST

An overview of diagnostic upgrade and experimental progress in the KTX

The Keda Torus eXperiment (KTX) is still operated in the commissioning phase, and preparation for the operation capability of the KTX phase II upgrade is underway. The diagnostics in the KTX have been greatly developed: (1) the terahertz interferometer has been upgraded to seven chords for electron density profile inversion; (2) a Thomson scattering system with a 5 Joule laser has been installed and commissioning is in progress; (3) a 3D movable probe system has been developed for the electromagnetic turbulence measurement; (4) double-foil soft x-ray imaging diagnostics have been set up and a bench test has been completed; (5) an edge capacitive probe has been installed for the radial electrical field measurement; (6) a multi-channel spectrograph system has been built for detecting impurities of carbon and oxygen. In addition, the design of a new compact torus injection system has been completed for feeding and momentum driving. Pilot research, such as the 3D reversed field pinch physics and electromagnetic turbulence, etc, have been conducted in the discharge status of the KTX. The 3D spectra characters of electromagnetic turbulence are firstly measured using a classical two-point technique by Langmuir probe arrays set on the 3D movable probe system and edge magnetic sensors. The forward scattering is collected by the interferometer system, which shows the potential for turbulence research. The electromagnetic turbulence is tentatively investigated in the KTX. The formation of a quasi-single-helicity state in the KTX regime is also preliminarily explored in simulation.

Size-Dependent Bacterial Toxicity of Hematite Particles.

Submicron-sized iron oxide particles can influence the activity of bacteria, but the exact mechanisms of oxide toxicity toward bacteria remain elusive. By using atomic force microscopy (AFM), soft X-ray tomography (Nano-CT), and Fourier transform infrared (FTIR) spectrometry, we show how the size-dependent interfacial interactions between hematite particles and bacteria in the absence of any ligands contribute to the antimicrobial properties against Gram-positive and Gram-negative bacterial strains. We found that surface adhesion between hematite particles and bacterial cells is initially dominated by Lifshitz van der Waals and electrostatic forces. Subsequently, the rapid formation of P-O-Fe bonds occurs, followed by changes in the structures of membrane proteins in 2 h, resulting in the loss of the structural integrity of the membrane within 10 h. Thus, particles can migrate into the cells. After contact with bacterial cells, reactive oxygen species are generated on the surface of hematite particles, leading to cell permeabilization. G- bacteria appear to be more susceptible to this process than G+ bacteria because the latter exhibit weaker adhesion forces toward hematite and benefit from the protective effects of the peptidoglycan layers. Our work revealed that hematite nanoparticles are more toxic to bacteria than microscaled particles due to their strong interfacial physicochemical interactions with the cells.

335-LB: Towards Generating Spatiotemporal Multiscale Models of Pancreatic ß Cells

To characterize biology, we must consider how molecular machines and organelles within a cell interact and traffic, similar to the importance of understanding traffic patterns in major cities. We use an imaging across scales approach to understand architectural changes that occur in pancreatic β-cells during insulin secretion. β-cells produce and release insulin in response to glucose and are therefore a target for diabetes therapies. Diabetes is a worldwide problem affecting hundreds of millions of people with increasing patient numbers every year. To acquire cellular architectural information, we are integrating data from cryo-electron tomography, soft x-ray tomography (SXT), and fluorescence microscopy. We used multiple glucose and GPCR agonist concentrations to investigate the cellular organization changes induced during insulin vesicle biogenesis and trafficking. The SXT method allows for investigating the 3D cellular architecture and is an ideal method for investigating cell-to-cell variabilities. Additionally, we are using machine learning methods for image analysis and autosegmentation which increased the number of conditions and samples we can analyze rapidly. Furthermore, we can use the information from cryo-ET and SXT along with with live cell imaging to assemble a data-driven, dynamic model of insulin granules within pancreatic β-cells. Furthermore, the SXT method provides a unique opportunity for comparing cell-to-cell heterogeneity and will be a useful technique for comparing differences between rodent and human primary cell architectures. The integration of data from different time and spatial scales represents a sophisticated convergence of our understanding of cellular structure and function, which will revolutionize biological discovery, open new dimensions of research, and accelerate advancements in healthcare. Disclosure K.L. White: None. J. Singla: None. R.C. Stevens: Board Member; Self; BirdRock Bio, Danaher Corp. Funding University of Southern California

Examining the optical intensity and magnetic field expansion factor in the open magnetic field regions associated with coronal holes

AbstractCoronal holes can be identified as the darkest regions in EUV or soft X-ray images with predominantly unipolar magnetic fields (LIRs) or as the regions with open magnetic fields (OMF). Our study reveals that only 12% of OMF regions are coincident with LIRs. The aim of this study is to investigate the conditions that affect the EUV intensity of OMF regions. Our results indicate that the EUV intensity and the magnetic field expansion factor of the OMF regions are weakly positively correlated when plotted in logarithmic scale, and that the bright OMF regions are likely to locate inside or next to the regions with closed field lines. We empirically determined a linear relationship between the expansion factor and the EUV intensity. The relationship is demonstrated to improve the consistency from 12% to 23%. The results have been published in Astrophysical Journal (Huang et al. 2019).

Overview of the high-definition x-ray imager instrument on the Lynx x-ray surveyor

Four NASA Science and Technology Definition Teams have been convened in order to develop and study four mission concepts to be evaluated by the upcoming 2020 Decadal Survey. The Lynx x-ray surveyor mission is one of these four large missions. Lynx will couple fine angular resolution (<0.5 arcsec HPD) x-ray optics with large effective area (~2 m^2 at 1 keV), thus enabling exploration within a unique scientific parameter space. One of the primary soft x-ray imaging instruments being baselined for this mission concept is the high-definition x-ray imager, HDXI. This instrument would use a finely pixelated silicon sensor array to achieve fine angular resolution imaging over a wide field of view (~22 x 22 arcmin). Silicon sensors enable large-format/small-pixel devices, radiation tolerant designs, and high quantum efficiency across the entire soft x-ray bandpass. To fully exploit the large collecting area of Lynx (~30x Chandra), with negligible or minimal x-ray event pile-up, the HDXI will be capable of much faster frame rates than current x-ray imagers. We summarize the planned requirements, capabilities, and development status of the HDXI instrument, and associated papers in this special edition will provide further details on some specific detector options.

Hard and soft X-ray imaging to resolve human ovarian cortical structures.

Laboratory and synchrotron X-ray tomography are powerful tools for non-invasive studies of biological samples at micrometric resolution. In particular, the development of phase contrast imaging is enabling the visualization of sample details with a small range of attenuation coefficients, thus allowing in-depth analyses of anatomical and histological structures. Reproductive medicine is starting to profit from these techniques, mainly applied to animal models. This study reports the first imaging of human ovarian tissue where the samples consisted of surgically obtained millimetre fragments, properly fixed, stained with osmium tetroxide and included in epoxydic resin. Samples were imaged by the use of propagation phase contrast synchrotron radiation micro-computed tomography (microCT), obtained at the SYRMEP beamline of Elettra light source (Trieste, Italy), and X-ray absorption microCT at the Theoretical Biology MicroCT Imaging Laboratory in Vienna, Austria. The reconstructed microCT images were compared with the soft X-ray absorption and phase contrast images acquired at the TwinMic beamline of Elettra in order to help with the identification of structures. The resulting images allow the regions of the cortex and medulla of the ovary to be distinguished, identifying early-stage follicles and visualizing the distribution of blood vessels. The study opens to further application of micro-resolved 3D imaging to improve the understanding of human ovary's structure and support diagnostics as well as advances in reproductive technologies.

X線天文衛星代替機(XARM) 搭載の軟Ｘ線撮像装置の開発状況

X線天文衛星代替機(XARM) 搭載の軟Ｘ線撮像装置の開発状況

Soft x-ray tomographic reconstruction of Heliotron J plasma for the study of magnetohydrodynamic equilibrium and stability

The preparation for an experimental soft x-ray tomography study on the Heliotron J (H-J) machine is carried out, with the objectives of evaluating the capability of the current soft x-ray tomographic system in terms of the identification of different mode structures and their poloidal rotation, and the axis shift with different plasma and machine parameters, and fixing the physics goals for the experimental study. These preparations were carried out via a simulated soft x-ray data set arising from different plasma conditions, such as magnetic islands, low beta and high beta. Soft x-ray tomography (SXT) is performed by the discrete pixel method including singular value decomposition and Phillips–Tikhonov regularization, to obtain clear and smooth images. The H-J soft x-ray tomography results from simulated soft x-rays for the equilibrium H-J plasma sensed the magnetic axis shift clearly and an estimate was also achieved. Successful reconstruction for mode structure m = 1/n = 1 was obtained along with the realization of the poloidal rotation of the structure. The reconstruction for the m = 2/n = 1 mode was not very clear for the current soft x-ray diagnostic design. Effective mode identification was not possible due to the lack of measurements. The SXT from the current soft x-ray diagnostic on H-J, the magnetic axis shift can be estimated and the m = 1/n = 1 mode can be studied. Study of higher poloidal modes is difficult with the current design.

Imaging Cancer Cells and their Interactions Within 3D Microenvironment - a Quantitative Study using Cryo Soft X-Ray Tomography

One of the most fundamental questions for cancer cell biologists is how the alterations of cellular morphology, as well as the organelles’ spatial re-organization, facilitate the cancer metastasis process. We are using soft x-ray tomography (SXT) to visualize and quantify all organelles in the cell in three dimensions during this collective behavior. This technique has also enabled us to account for the cell heterogeneity and to examine a large number of cells and their interactions within a created micro-environment. SXT is a non-invasive imaging technique with high spatial resolution (∼35nm). It is a quantitative imaging technology that generates high contrast views of organelles within intact cells in their near-native state. Illuminating cells with soft x-ray takes the advantage of “water-window” property that image contrast comes directly from the absorption of cell constituents. The absorption is also linear with the concentration of bio-organic molecules. Each voxel in an organelle has a denoted value called linear absorption coefficient (LAC) that can be used as a fingerprint for different organelles. We have created a 3D microenvironment using different concentrations of collagen that have resulted in different pore sizes for cancer cells (HT1080) to crawl through. With different physical limitations, we observed the distinct cellular morphologies during different states. We can quantitatively study the variaitons in nuclear size and shapes, the mitochrondria spatial distributions and volumes, the number and volume of lipid droplets and analyze the ratios between euchromatin and heterochromatin.

Mesoscale Architecture of Beta Cells Upon Glucose and Ex-4 Stimulation

To understand biology we must consider how molecular machines and organelles within a cell interact and traffic, similar to the importance of understanding traffic patterns in major cities. We use an imaging across scales approach to understand architectural changes that occur in pancreatic β-cells during insulin secretion. β-cells produce and release insulin in response to glucose and are therefore a target for diabetes therapies. Diabetes is a worldwide problem affecting hundreds of millions of people with increasing patient numbers every year. To acquire cellular architectural information, we are integrating data from cryo-electron tomography, soft x-ray tomography (SXT), and fluorescence microscopy. We imaged INS-1E cells (rat pancreatic β-cell line) under multiple glucose and GPCR agonist concentrations to investigate the cellular organization changes induced during insulin vesicle biogenesis and trafficking. The SXT method allows for investigating the 3D cellular architecture and is an ideal method for investigating cell-to-cell variabilities. Additionally, we are using machine learning methods for image analysis and autosegmentation which increased the number of conditions and samples we can analyze rapidly. Furthermore, we can use the information from cryo-ET and SXT along with with live cell imaging to assemble a data-driven, dynamic model of insulin granules within pancreatic β-cells. The integration of data from different time and spatial scales represents a sophisticated convergence of our understanding of cellular structure and function, which will revolutionize biological discovery, open new dimensions of research, and accelerate advancements in healthcare.

CT Scans of Single Cells with Soft X-Ray Tomography

CT Scans of Single Cells with Soft X-Ray Tomography

Characterization of a BSI sCMOS for soft X-ray imaging spectroscopy

In recent years, significant progress has been made on Complementary Metal Oxide Semiconductor (CMOS) devices, which have been proposed as X-ray imaging spectroscopes for future space astronomy missions. We tested a newly developed backside-illuminated scientific CMOS (BSI sCMOS) device, which is treated as a soft X-ray imaging spectroscopy. This BSI sCMOS has an array of 2048×2048 pixels with a pixel size of 11 μm and an epitaxial thickness of 3.6 μm. It is an active pixel sensor with fast readout, low power consumption and low readout noise. We investigated the performance of this BSI sCMOS as a soft X-ray detector. The energy resolution reaches 192 eV at 5.9 keV near room temperature. When the detector is cooled down to −20̂C, the results show the readout noise to be approximately 1.5 e−, the dark current to be 159 e−/pixel/s, and the energy resolution to be 187 eV (3.2%) at 5.9 keV . Meanwhile, the soft X-rays down to the carbon line (277 eV) can be clearly identified.

X-ray tomography shows the varying three-dimensional morphology of gold nanoaggregates in the cellular ultrastructure.

The processing of nanoparticles inside eukaryotic cells is a key step in many wanted and unwanted nano-bio-interactions. In order to understand the effects and functions of the intracellular aggregates that are formed, their properties and their interaction with the biological matrix must be characterized. High quality synchrotron soft X-ray tomography (SXT) data were obtained from cells containing gold nanoparticles that are commonly applied as tools for optical probing or drug delivery. 3D volume rendering of both cellular organelles and the nanoparticle aggregates of different sizes in the intact cells of two cell lines reveals variation in localization, size, shape and density of the intracellular gold nanoaggregates. The dependence of such variation on incubation time and cell type, as well as on the influence of pre-aggregation of primary nanoparticles is shown. The SXT results provide a detailed picture of intracellular aggregation and will improve the design of safe and efficient nanoparticle platforms for biomedical use.