An X-ray grating interferometer was installed at the BL13W beamline of Shanghai Synchrotron Radiation Facility (SSRF) for biomedical imaging applications. Compared with imaging results from conventional absorption-based micro-computed tomography, this set-up has shown much better soft tissue imaging capability. In particular, using the set-up, the carotid artery and the carotid vein in a formalin-fixed mouse can be visualized in situ without contrast agents, paving the way for future applications in cancer angiography studies. The overall results have demonstrated the broad prospects of the existing set-up for biomedical imaging applications at SSRF.

Hollow nanostructures with enlarged surface areas are highly attractive electrode materials for supercapacitors. In this work, the size-dependent synthesis of hollow Co3O4 nanocubes via a facile ionic exchange reaction between Co-Fe Prussian blue analogues (PBAs) and alkali solution is reported. By adjusting the concentration of sodium citrate to control the reaction kinetics during nucleation and growth, four different sizes of Co-Fe PBAs were synthesized. It was also found that a Co-Fe PBA of about 140 nm can be easily converted into a well-defined internal hollow structure, while Co-Fe PBAs with smaller or larger sizes are challenged in generating a hollow structure. Benefitting from the inner voids and thin shell architecture, the derived hollow Co3O4 nanocubes exhibit a high specific capacity of 296.6C cm−2 at 2 mA cm−2, and a rate capability of 64.5% when the current density is increased to 60 mA cm−2. Furthermore, a hybrid supercapacitor (HSC) was fabricated with hollow Co3O4 nanocubes as the cathode and activated carbon as the anode, respectively. The HSC provided a maximum energy density of 14.1 Wh kg−1 at 464.7 W kg−1. Moreover, it retained the excellent cycling stability of 85.7% of the original capacity over 5000 continuous charging and discharging processes.

No abstract

BackgroundThe use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties.MethodsThe X-ray phase-contrast microtomography quantitative imaging method was used to investigate the microstructure of ginseng, and the phase-retrieval method is also employed to process the experimental data. Four different ginseng samples were collected and investigated; these were classified according to their species, production area, and sample growth pattern.ResultsThe quantitative internal characteristic microstructures of ginseng were extracted successfully. The size and position distributions of the calcium oxalate cluster crystals (COCCs), important secondary metabolites that accumulate in ginseng, are revealed by the three-dimensional quantitative imaging method. The volume and amount of the COCCs in different species of the ginseng are obtained by a quantitative analysis of the three-dimensional microstructures, which shows obvious difference among the four species of ginseng.ConclusionThis study is the first to provide evidence of the distribution characteristics of COCCs to identify four types of ginseng, with regard to species authentication and age identification, by X-ray phase-contrast microtomography quantitative imaging. This method is also expected to reveal important relationships between COCCs and the occurrence of the effective medicinal components of ginseng.