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Formation of chirality-specific protein corona on gold nanoparticles promotes recognition by lipoproteins, complements, and acute phase proteins that mediates LDL receptor-involved cell uptake and tissue accumulation in vivo.

Driven by the development of advanced x-ray optics such as Fresnel zone plates, nano-resolution full-field transmission x-ray microscopy (Nano-CT) has become a powerful technique for the non-destructive volumetric inspection of objects and has long been developed at different synchrotron radiation facilities. However, Nano-CT data are often associated with random sample jitter because of the drift or radial/axial error motion of the rotation stage during measurement. Without a proper sample jitter correction process prior to reconstruction, the use of Nano-CT in providing accurate 3D structure information for samples is almost impossible. In this paper, to realize accurate 3D reconstruction for Nano-CT, a correction method based on a feature detection neural network, which can automatically extract target features from a projective image and precisely correct sample jitter errors, is proposed, thereby resulting in high-quality nanoscale 3D reconstruction. Compared with other feature detection methods, even if the target feature is overlapped by other high-density materials or impurities, the proposed Nano-CT correction method still acquires sub-pixel accuracy in geometrical correction and is more suitable for Nano-CT reconstruction because of its universal and faster correction speed. The simulated and experimental datasets demonstrated the reliability and validity of the proposed Nano-CT correction method.

Nano-resolution full-field transmission X-ray microscopy has been successfully applied to a wide range of research fields thanks to its capability of non-destructively reconstructing the 3D structure with high resolution. Due to constraints in the practical implementations, the nano-tomography data is often associated with a random image jitter, resulting from imperfections in the hardware setup. Without a proper image registration process prior to the reconstruction, the quality of the result will be compromised. Here a deep-learning-based image jitter correction method is presented, which registers the projective images with high efficiency and accuracy, facilitating a high-quality tomographic reconstruction. This development is demonstrated and validated using synthetic and experimental datasets. The method is effective and readily applicable to a broad range of applications. Together with this paper, the source code is published and adoptions and improvements from our colleagues in this field are welcomed.

The differential phase computed tomography (DP-CT) imaging is a kind of X-ray-phase-based CT methods, which is widely used in various X-ray imaging laboratories. At present, a collection of projections with the horizontal direction (perpendicular to the sample rotation axis) DP information is often acquired in DP-CT. In an ideal experiment, if the background is zero, then we can accurately reconstruct the information of each direction of the sample with horizontal data only. Actually, background information will produce streaking artifacts to affect the resolution in directions other than the horizontal direction. To mitigate the streaking artifacts in the conventionally reconstructed DP-CT images. This study develops a novel analytical DP-CT reconstruction framework by jointly using the bilateral DP information obtained along two perpendicular directions. In addition, a new data acquisition scheme is also proposed to quickly acquire the bilateral DP signal without the need of changing the direction of refraction signal acquisition. Experimental results demonstrate that this new algorithm is able to greatly reduce the streaking artifacts on DP-CT images.

The degradation of nickel-rich cathode materials for lithium-ion batteries upon prolonged electrochemical cycling features a complicated interplay among electronic structure, lattice configuration,...

Nano-resolution synchrotron X-ray spectro-tomography has been demonstrated as a powerful tool for probing the three-dimensional (3D) structural and chemical heterogeneity of a sample. By reconstructing a number of tomographic data sets recorded at different X-ray energy levels, the energy-dependent intensity variation in every given voxel fingerprints the corresponding local chemistry. The resolution and accuracy of this method, however, could be jeopardized by non-ideal experimental conditions, e.g. instability in the hardware system and/or in the sample itself. Herein is presented one such case, in which unanticipated sample deformation severely degrades the data quality. To address this issue, an automatic 3D image registration method is implemented to evaluate and correct this effect. The method allows the redox heterogeneity in partially delithiated Li x Ta0.3Mn0.4O2 battery cathode particles to be revealed with significantly improved fidelity.

The equiaxed solidification of Al–20Cu alloy under different cooling rates was investigated using in-situ synchrotron X-ray radiography. The results showed that mean grain size increases rapidly at...

The effects of the white-light X-ray and 170-keV proton beam irradiation on the electrical and optical characteristics of the InGaN/GaN multiple quantum wells (MQWs) light-emitting diodes (LEDs) are analyzed and compared. Different from the negative effects of the proton irradiation, the X-ray irradiation shows positive effects on the LEDs’ performance. In detail, after the 100 Mrad(Si) X-ray irradiation, the p-n junction resistance decreases from the original 2.51 to $2.08~\Omega $ , the light output power increases from 170 to 203 mW (at a forward voltage of 3.2 V), and the maximal external quantum efficiency (EQE) increases from 56.7% to 61.8%. Based on the ABC model fittings, both the Shockley–Read–Hall recombination rate and the radiative recombination rate in the MQWs are improved by the X-ray irradiation. The Hall effect measurements reveal the chemical bond breaking of the Mg-H complex in the p-type GaN. Therefore, the improvement of the LED by the X-ray irradiation should be caused by the chemical bond variations of the defect-related complex in the MQWs and the Mg-H complex in the p-type GaN.

X-ray tomography is widely used in diverse research domains owing to its capacity for observing high-resolution three-dimensional structures nondestructively. However, ring artifacts appear in the tomographic reconstruction because of the inconsistent response of detector pixels, seriously affecting the image quality and causing nonuniform bias. To solve this problem, a method for correction of ring artifacts based on Swin-Conv-U-Net is proposed for x-ray tomography. When applied to simulation and experimental data, the proposed method achieves high accuracy and strong robustness and shows advantages over several classical methods in quantitative and qualitative evaluation.

Transmission X-ray microscopy (TXM) can acquire a full-field projection image with spatial resolution of tens of nanometers using one-time exposure. Thus, it is easy to combine this imaging method with computed tomography and to get three-dimensional (3D) morphology information of samples. In this chapter, we will introduce the methods of TXM and corresponding operation principles, the application examples of energy materials and devices, and the possible development of these imaging technologies.

The analysis of organic residues in pottery can provide abundant information on the lives of ancient people, including the natural resources consumed, the techniques applied, the functions of pottery, and so on. In this paper, a variety of methods, including FT-IR (Fourier transform infrared spectroscopy), GC–MS (gas chromatography-mass spectrometry), SEM (scanning electron microscopy) and SR-μCT (synchrotron radiation micro-computed tomography), have been employed to characterize the carbonized residues from an amphora, unearthed from the Changning site, Qinghai Province, Northwest China. The pottery residues were identified as birch bark tar, so ancient people in China could have used the particular local plant resources, birch bark, to produce tar as early as the Qijia cultural period (c. 4,000–3,500 bp). The birch bark tar could have been used to make composite tools discovered at the Changning site, and the amphora has probably been used for tar production. This, to our knowledge so far, is the earliest evidence for the use of birch bark tar in China. Due to the special geographical location of the Gansu-Qinghai Region, and the transition of subsistence strategy during the Qijia cultural period, the production and utilization of birch bark tar could not rule out the possibility of western influence, which needs further evidence.

In this paper, two kinds of nanoporous Mg are prepared by a physical vapor deposition method, and their hydrogen generation properties are investigated based on the hydrolysis reaction with salt water. The results indicate that cell-like nanoporous Mg has higher hydrogen generation amount of 800 ml g−1 and hydrogen generation rate of 48.1 ml g−1 min−1 than block-like nanoporous Mg, while block-like nanoporous Mg with the substrate shows better hydrogen generation property of 933 ml g−1 and 78.4 ml g−1 min−1. The effects of concentration of salt water and temperature on their hydrogen generation property have been investigated. In order to explain their excellent hydrogen generation properties, electrode potential and specific surface area of different Mg materials are examined. The results indicate that cell-like nanoporous Mg has a more negative potential (−2.410 V (vs.RHE)) than block-like nanoporous Mg (−2.279 V (vs.RHE)), and a higher specific surface area of 26.7 m2 g−1 than block-like nanoporous Mg of 0.9 m2 g−1, both of which are more negative and higher than that of Mg plate and Mg alloy plate. Thus, it can be concluded that more negative potential and higher specific surface area of nanoporous Mg are the reasons for their better hydrogen generation property.

Effect of the melt superheat on equiaxed solidification of Al-20 wt% Cu alloy was investigated by in-situ synchrotron radiography at Beijing Synchrotron Radiation Facility. For comparison, the corresponding DSC analysis was also conducted. It was found that the grain size decreased with increasing the melt superheat. The relationship between the final mean grain size and the melt superheat can be expressed as: d = 4919.3 × Δ T - 0.33 . During solidification, the mean grain size increased sharply in the first 70 s, then reached the final grain size gradually. Furthermore, with increasing the melt superheat, the mean nucleation rate increased, which can be attributed to the fact that increasing the melt superheat led to an increase in nucleation undercooling, and the growth rate and the duration of free growth stage decreased. As the melt superheat increased from 100 °C to 160 °C, the mean nucleation rate increased by 78.2% while the mean growth rate only decreased by 19.3%, which indicated that the high mean nucleation rate and the consequent low mean growth rate may be the real reasons for grain refinement. The increased nucleation density caused earlier growth deceleration due to solutal impingement effects.

In situ synchrotron X-ray radiography was used to study the effect of direct current (DC) on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm 2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.

Adding silica nanofiller in silicone rubber can toughen the matrix 3 orders in terms of fracture energy, which is far larger than most other nanofiller–rubber systems. To unveil the astonishing toughening mechanism, we employ in situ synchrotron radiation X-ray nanocomputed tomography (Nano-CT) technique with high spatial resolution (64 nm) to study the structural evolution of silica nanofiller in silicone rubber matrix at different strains. The imaging results show that silica nanofiller forms three-dimensional connected network, which couples with silicone chain network to construct a double-network structure. Stress-induced phase separation between silica nanofiller and silicone polymer chain networks is observed during tensile deformation. Unexpectedly, though the spatial position and morphology of nanofiller network changes greatly at large strains, the connectivity of nanofiller network shows negligible reduction. This indicates that nanofiller network undergoes destruction and reconstruction simult...

As one of the HEPS project beamlines, zone plate based full-field transmission x-ray microscopy (TXM) beamline will provide imaging tool with spatial resolution down to 20nm and exposure time of sub-second, along with different imaging mode such as absorption, Zernike phase and XANES. Because HEPS will operate a nearly diffraction-limited storage ring (less than 60pm·rad), how to utilize the feature of low emittance becomes interesting and it is some challenging to satisfy the zone plate imaging with enough illumination angle and field-of-view. Within the optimized conceptual design, beam shaper condenser instead of capillary was selected to focus x-rays to sample and give enough illumination angle to zone plate, and red-shift undulator radiation was used to improve beamline efficiency.

Metal-nitrogen-carbon (M-N-C) materials show great advantages for catalyzing the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs). However, both the low density of single atomic (SA) MNx active sites and restricted mass transfer render these M-N-C based air electrodes inferior in cell performance. In this study, a new ZIF8-derived Fe-N-C catalyst/electrode design combining local chemistry tuning and primary morphology tailoring to address the above two critical issues is shown. The introduction of nitrogen-carbon defects in ZIF8 host enables a controlled atomic-scale dispersion of FeNx moieties, increasing their content in support materials. Also, the simultaneous structural arrangement of individual ZIF8 nano-grains endows the catalyst with a unique porous micro-spheric morphology. This result in an advanced 3D air electrode featuring dense SA FeNx sites and ample, multiscale macro-sized pore channels, which can significantly increase the intrinsic catalytic activity, facilitate bulk mass transport, and generate more effective triple-phase interfaces for ORR. The present catalyst/electrode design exhibits a record large peak power density of ca. 0.60 W cm−2 under practical air conditions. This approach provides a feasible way for boosting the air cathode interfacial ORR and further enlightens electrode designs for energy devices involving multiphase electrochemical reactions.

With the development of full-field transmission X-ray microscopy (TXM) for research in biology, life science, material science and physics, zone plate-based full-field TXM is becoming a powerful tool for obtaining quantitative internal structural and chemical information at the nanoscale when combined with spectroscopic imaging. For the TXM beamline design, the best choice is to match the phase space needed by the zone plate from the source point. However, for the nearly diffraction-limited synchrotron radiation sources, it is not easy to fully match the needed phase space due to its low-emittance. Using redshift radiation from an undulator, under consideration of experimental requirements and the heat load effect, this paper describes the design of TXM beamline at the nearly diffraction-limited High Energy Photon Source (HEPS). In this design, not only sufficient illumination angle can be acquired, but also a nearly annular illumination can be obtained to match the illumination required for zone plate imaging. Furthermore, about two times photon flux can be obtained at source point and the photons can be fully used in this design using redshift undulator radiation. The presented design can also be informative for the same kind of beamline design at other nearly diffraction-limited synchrotron photon sources.

Growth-year authentication has extraordinary significance for plant growth, structure and development research, and has a wide range of applications in value assessment of economic crops. Panax ginseng is the most commonly used medicinal plant in Asian countries. The fix number of growth-year is an important quality evaluation which is difficult to be obtained accurately in current technical conditions. Preliminary authentication theory for growth-year has been described in previous studies using a short-lived perennial medicinal plant (Paeonia lactiflora pall.) as the research material. In this research, we focused on the growth-year estimation in ginseng cultivars, and attempt to explore the age estimation method for vascular plants according to mathematical simulation of the root structure development. Micro data was obtained from 204 individuals of 3 different kinds of ginseng cultivars, which have a series of gradient age and a clear growth record. Outer diameter of the vascular cambium (b) and the radius of cross section (r) were measured with ordinary stereo microscope. We further designed and established two different kinds of authentication model based on the taproot structure development for growth year authentication (P =β*M-α and M = K*X1 (a) (1) X2 (a) (2) ). Moreover, the models were applied to identify the growth year of ginseng without damage using Micro-CT or DEI reconstruction. A potential method, have been recently described, the age of ginseng can be analyzed by telomere length and telomerase activity. However, we found that there are different results indicated in other species. We concluded that microscopic methods perceived currently were provided a more effective means for growth-year authentication.

Redox phase transformations are relevant to a number of metrics pertaining to the electrochemical performance of batteries. These phase transformations deviate from and are more complicated than the conventional theory of phase nucleation and propagation, owing to simultaneous changes of cationic and anionic valence states as well as the polycrystalline nature of battery materials. Herein, we propose an integrative approach of mapping valence states and constructing chemical topographies to investigate the redox phase transformation in polycrystalline layered oxide cathode materials under thermal abuse conditions. We discover that, in addition to the three-dimensional heterogeneous phase transformation, there is a mesoscale evolution of local valence curvatures in valence state topographies. The relative probability of negative and positive local valence curvatures alternates during the layered-to-spinel/rocksalt phase transformation. The implementation of our method can potentially provide a universal approach to study phase transformation behaviors in battery materials and beyond., Here the authors demonstrate a spectroscopic and imaging approach to study redox solid-state phase transformation in lithium ion cathode materials under thermal abuse conditions. The valence curvature of the propagation front alternates as a result of local chemical and structural heterogeneities.

Synchrotron radiation X-ray computed tomography (CT) enables nondestructive visualization of 3D morphological and chemical changes inside a sample and has become a powerful analysis tool to monitor reactive parts and their chemical states. However, synchrotron radiation CT imaging of specimens with lateral extensions much larger than the acceptance window of detectors is rather problematic due to strong absorption of X-rays in the lateral directions. On the other hand, X-ray computed laminography (CL) permits 3D imaging of flat samples while X-ray diffraction enhanced imaging (DEI) can provide high-quality results with different imaging contrasts such as absorption, phase and dark-field for samples with weak absorptions. Combining CL and DEI together, we have developed a multi-contrast DEI-CL system at the 4W1A beamline of the Beijing Synchrotron Radiation Facility for this kind of sample. Here we reported its design, implementation, and preliminary experimental results of carbon fiber reinforced polymer laminates with three kinds of imaging contrasts. The results have demonstrated the validity of this DEI-CL system. It will be helpful to push the applications of the state-of-the-art synchrotron radiation methods and instruments towards cutting-edge research. Graphical abstract ᅟ.

A three-image algorithm is proposed in order to retrieve the absorption, refraction and ultra-small-angle X-ray scattering (USAXS) properties of the object in X-ray analyzer-based imaging. Based on the Gaussian fitting to the rocking curve, the novel algorithm is theoretically derived and presented, and validated by synchrotron radiation experiments. Compared with multiple-image radiography, this algorithm only requires a minimum of three intensity measurements, and is therefore advantageous in terms of simplified acquisition procedure and reduced data collection times, which are especially important for specific applications such as in vivo imaging and phase tomography. Moreover, the retrieval algorithm can be specialized to particular cases where some degree of a priori knowledge on the object is available, potentially reducing the minimum number of intensity measurements to two. Furthermore, the effect of angular mis-alignment on the accuracy of the retrieved images was theoretically investigated, which can be of use in image interpretation and optimization of the data acquisition procedure.

To predict potential medical value or toxicity of nanoparticles (NPs), it is necessary to understand the chemical transformation during intracellular processes of NPs. However, it is a grand challenge to capture a high-resolution image of metallic NPs in a single cell and the chemical information on intracellular NPs. Here, by integrating synchrotron radiation-beam transmission X-ray microscopy (SR-TXM) and SR-X-ray absorption near edge structure (SR-XANES) spectroscopy, we successfully capture the 3D distribution of silver NPs (AgNPs) inside a single human monocyte (THP-1), associated with the chemical transformation of silver. The results reveal that the cytotoxicity of AgNPs is largely due to the chemical transformation of particulate silver from elemental silver (Ag(0))n, to Ag(+) ions and Ag-O-, then Ag-S- species. These results provide direct evidence in the long-lasting debate on whether the nanoscale or the ionic form dominates the cytotoxicity of silver nanoparticles. Further, the present approach provides an integrated strategy capable of exploring the chemical origins of cytotoxicity in metallic nanoparticles.

A description of the rocking curve in diffraction enhanced imaging (DEI) is presented in terms of the angular signal response function and a simple multi-information retrieval algorithm based on the cosine function fitting. A comprehensive analysis of noise properties of DEI is also given considering the noise transfer characteristic of the X-ray source. The validation has been performed with synchrotron radiation experimental data and Monte Carlo simulations based on theGeant4toolkit combined with the refractive process of X-rays, which show good agreement with each other. Moreover, results indicate that the signal-to-noise ratios of the refraction and scattering images are about one order of magnitude better than that of the absorption image at the edges of low-Zsamples. The noise penalty is drastically reduced with the increasing photon flux and visibility. Finally, this work demonstrates that the analytical method can build an interesting connection between DEI and GDPCI (grating-based differential phase contrast imaging) and is widely suitable for a variety of measurement noise in the angular signal response imaging prototype. The analysis significantly contributes to the understanding of noise characteristics of DEI images and may allow improvements to the signal-to-noise ratio in biomedical and material science imaging.

High resolution time-resolved X-ray imaging with synchrotron radiation has been used to in situ observe the growth behavior of Cu6Sn5 intermetallic compounds (IMCs) during solidification in Sn-6.5 Cu and Sn-6.5 Cu-0.2 Al (wt. %) solders under applied direct current (DC) field. The morphological evolution of Cu6Sn5 with I-like, X-like, Y-like and bird-like shapes is directly observed. It is shown that trace levels of Al have a marked effect on the solder microstructures and refining the size of the primary Cu6Sn5. The solidification pathway leading to the refinement is observed in real time using synchrotron microradiography. After adding the trace Al, I-like shapes bifurcate into X-like shapes. Furthermore, when DC field with 10 A/cm(2) is applied, both the growth rate and the mean size of Cu6Sn5 are increased but decreased when 100 A/cm(2) is applied. Meanwhile, the effect of thermodynamic potential barrier caused by DC field on the growth behavior of Cu6Sn5 is discussed. (C) 2014 Elsevier Ltd. All rights reserved.

Carbon fiber composites have been wildly used in aerospace industry due to the excellent performance. However, the research on defect evolution law and the performance analysis have been limited by the lack of effective tools. Two kinds of computed tomography (CT) slice images of carbon fiber composites, x-ray attenuation contrast and phase contrast, were obtained with the diffraction enhancement imaging (DEI) device at Beijing Synchrotron Radiation Facility (BSRF). The structure details and the defects in the sample could be clearly distinguished from the image. Moreover, phase contrast CT provides higher contrast and can identify the defects difficult to be recognized in attenuation contrast CT. DEI provides a method for in-situ observation of the carbon fiber composites and would be a valuable tool for the development of carbon fiber composite material.

Synchrotron X-ray radiography was used to in situ study the interface diffusion behavior and microstructural evolution during the melting and solidification of Al/Cu bimetal. During the solidification, the dendritic growth around the interface is mainly dominated by the variation of Cu concentration and thermal field. Four transition zones of solute profile around the interface were identified to be I (alpha-Al), II (Al + Al2Cu), III (Al2Cu) and IV (AlCu, Al3Cu4 and Al2Cu3), respectively. During the melting, the concentration variations of Al and Cu around the interface were quantitatively analyzed through the extraction of gray level from sequenced X-ray images. The diffusion coefficients of Cu in liquid Al were calculated from the known concentration variations by an inverse method based on Fick's second law. The diffusion coefficients of Cu in Al were found to follow linear Arrhenius equation dependencies with the pre-exponential factor of 2.83 x 10(-5) m(2) s(-1) and the activation energy of 96.0 kJ mol(-1) in a temperature range of 893-970 K. (C) 2014 Elsevier B.V. All rights reserved.

The macroscopic distribution of multi-crystalline structure (MCS) in a sapphire boule grown by Kyropoulos technique was characterized using polariscope. The morphology and texture of subgrains from [0001], [11 (2) over bar0] and [(1) over bar 100] orientations were investigated using Synchrotron radiation white-beam topography technique. The morphology of subgrains was found to be diverse from crystallographic orientation. The relative angles between subgrains are smaller than 1 degrees. The defect structure on a basal-plane specimen from the lower part of the "shoulder" was examined by X-ray rocking curve and chemical etching technique. It was found that the defect concentration changes drastically near MCS center. The nature of spatial distribution of MCS and the defect distribution near MCS in a grown boule was discussed in detail.