Portable X-ray powder diffractometer for the analysis of art and archaeological materials

Phase identification based on nondestructive analytical techniques using portable equipment is ideal for the analysis of art and archaeological objects. Portable(p)-XRF and p-Raman are very widely used for this purpose, yet p-XRD is relatively rare despite its importance for the analysis of crystalline materials. This paper overviews 6 types of p-XRD systems developed for analysis of art and archaeological materials. The characteristics of each system are compared. One of the p-XRD systems developed by the authors was brought to many museums as well as many archeological sites in Egypt and Syria to characterize the cultural heritage artifacts, e.g., amulet made of Egyptian blue, blue painted pottery, and Islamic pottery from Egypt, jade from China, variscite from Syria, a Japanese classic painting drawn by Korin Ogata, and oil paintings drawn by Taro Okamoto. Practical application data are shown to demonstrate the potential ability of the method for analysis of various art and archaeological materials.     

Direct measurement of energetic electrons coupling to an imploding low-adiabat inertial confinement fusion capsule

We have imaged hard x-ray (>100 keV) bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. We measure 570 J in electrons with E>100 keV impinging on the fusion capsule under ignition drive conditions. This translates into an acceptable increase in the adiabat α, defined as the ratio of total deuterium-tritium fuel pressure to Fermi pressure, of 3.5%. The hard x-ray observables are consistent with detailed radiative-hydrodynamics simulations, including the sourcing and transport of these high energy electrons.     

Structure of χ3-Borophene Studied by Total-Reflection High-Energy Positron Diffraction (TRHEPD)

We have investigated the structure of χ₃-borophene on Ag(111), a monolayer material of boron atoms, via total-reflection high-energy positron diffraction (TRHEPD). By comparing the experimental rocking-curves with ones for several structures calculated by using dynamical diffraction theory, we confirmed that the χ₃-borophene layer has a flat structure. The distance from the topmost layer of the metal crystal is 2.4 Å, which is consistent with results reported by X-ray standing wave-excited X-ray photoelectron spectroscopy. We also demonstrated that the in-plane structure of χ₃-borophene is compatible with the theoretical predictions. These structural properties indicate that χ₃-borophene belongs to a group of epitaxial monolayer sheets, such as graphene, which have weak interactions with the substrates.     

Failure-Experiment-Supported Optimization of Poorly Reproducible Synthetic Conditions for Novel Lanthanide Metal-Organic Frameworks with Two-Dimensional Secondary Building Units**

Novel metal–organic frameworks containing lanthanide double-layer-based secondary building units (KGF-3) were synthesized by using machine learning (ML). Isolating pure KGF-3 was challenging, and the synthesis was not reproducible because impurity phases were frequently obtained under the same synthetic conditions. Thus, dominant factors for the synthesis of KGF-3 were identified, and its synthetic conditions were optimized by using two ML techniques. Cluster analysis was used to classify the obtained powder X-ray diffractometry patterns of the products and thus automatically determine whether the experiments were successful. Decision-tree analysis was used to visualize the experimental results, after extracting factors that mainly affected the synthetic reproducibility. Water-adsorption isotherms revealed that KGF-3 possesses unique hydrophilic pores. Impedance measurements demonstrated good proton conductivities (σ=5.2×10⁻⁴ S cm⁻¹ for KGF-3(Y)) at a high temperature (363 K) and relative humidity of 95 % RH.     

Synthesis of porous C/Fe3O4 microspheres by spray pyrolysis with NaNO3 additive for lithium-ion battery applications

In this work, we successfully synthesized porous C/Fe₃O₄ microspheres by spray pyrolysis at 700ºC with a sodium nitrate (NaNO₃) additive in the precursor solution. Furthermore, we studied their electrochemical properties as anode material for Li-ion batteries. The systematic studies by various characterization techniques show that NaNO₃ catalyzes the carbonization of sucrose and enhances the crystallization of Fe₃O₄. Moreover, an aqueous etching can easily remove sodium compounds to produce porous C/Fe₃O₄ microspheres with large surface areas and pore volumes. The porous C/Fe₃O₄ microspheres exhibit a reversible capacity of ~780 mAh g^–1 in the initial cycles and ~520 mAh g^–1 after 30 cycles at a current density of 50 mA g^–1. Moreover, a reversible capacity of ~400 mAh g^–1 is attainable after 200 cycles, even at a high current density of 500 mA g^–1. The wide range of pores produced from the removal of sodium compounds might enable easy electrolyte penetration and facilitate fast Li-ion diffusion, while the N-doping can promote the electronic conductivity of the carbon. These features of porous C/Fe₃O₄ microspheres led to the improved electrochemical properties of this sample.

Graphical Abstract

     

Evaluation of the accuracy of hTERT gene aberrant methylation using electrochemical hybridization assay and liquid-based cytology in screening for oral squamous cell carcinoma

In order to improve the survival rate of oral squamous cell carcinoma (OSCC) patients, a reliable diagnostic method for early OSCC detection is required that is minimally invasive, less burdensome to the patient, and has high sensitivity and specificity. Therefore, we performed the detection of abnormal methylation at three locations in the hTERT promoter region of oral exfoliated cells by employing the ferrocenylnaphthalene diimide (FND)-based electrochemical hybridization assay (FND-EHA) using three types of DNA probe-immobilized electrodes. We also performed liquid cytology using oral exfoliated cells and compared these obtained data to evaluate whether FND- EHA can be used as an OSCC screening system. The results showed a good correlation between this method and conventional OSCC screening, and cytology. In addition, FND-EHA was also able to determine samples that had been ambiguously determined by liquid cytology. This indicates that FND-EHA may be useful as an OSCC screening system.