Automatic detection and visualization system for coronary artery calcification using optical frequency domain imaging

Artificial Life and Robotics - Percutaneous coronary intervention (PCI) is mainly used in the treatment of stenosis of the coronary arteries of the heart characteristic of coronary artery disease,...     

Green emitting β$\ubeta$-SiAlON:Eu2+ phosphors derived from chemically modified perhydropolysilazanes

We report the first synthesis of β-SiAlON:Eu²⁺ phosphors from single-source precursors, perhydropolysilazane (PHPS), chemically modified with Al(OCH(CH₃)₂)₃, and EuCl₂. The reactions occurring during the precursor synthesis and the subsequent thermal conversion of polymeric precursors into β-SiAlON:Eu²⁺ phosphors have been studied by a complementary set of analytical techniques, including infrared spectroscopy, gas chromatography–mass spectrometry, thermogravimetry–mass spectrometry, X-ray diffraction (XRD), photoluminescence spectroscopy, and scanning electron microscopy. It has been clearly established that Al(OCH(CH₃)₂)₃ immediately reacted with PHPS to afford N–Al bonds at room temperature, whereas N–Eu bond formation was suggested to proceed above 600°C accompanied by the elimination of HCl up to 1000°C in flowing N₂. The subsequent 1800°C-heat treatment for 1 h under an N₂ gas pressure at 980 kPa allowed converting the single-source precursors into fine-grained β-SiAlON:Eu²⁺ phosphors. XRD analysis revealed that the Al/Si of .09 was the critical atomic ratio in the precursor synthesis to afford single-phase β-SiAlON (z = .55). Moreover, Eu²⁺-doping was found to efficiently reduce the carbon impurity in the host β-SiAlON. The polymer-derived β-SiAlON:Eu²⁺ phosphors exhibited green emission under excitation at 460 nm and achieved the highest green emission intensity at the critical dopant Eu²⁺ concentration at 1.48 at%.     

Iridium‐Catalyzed [2+2+2] Cycloaddition of α,ω‐Diynes with Cyanamides

The complex [Ir(cod)Cl]₂/DPPF or rac‐BINAP is an efficient catalyst for the [2+2+2] cycloaddition of α,ω‐diynes with cyanamides. A wide range of cyanamides derived from secondary amines are good coupling partners for α,ω‐diynes. The reaction of unsymmetrical α,ω‐diynes possessing two different internal alkyne moieties with cyanamides is regioselective. A competitive experiment showed that cyanamide is more reactive than nitrile. This higher reactivity of cyanamide than nitrile was analyzed based on density functional theory (DFT) calculations at the B3LYP level.

     

Estimation of habit-related information from male voice data using machine learning-based methods

Artificial Life and Robotics - According to a survey on the cause of death among Japanese people, lifestyle-related diseases (such as malignant neoplasms, cardiovascular diseases, and pneumonia)...     

Screening chloride Li-ion conductors using high-throughput force-field molecular dynamics

The realization of high-energy-density all-solid-state Li-ion batteries requires materials exhibiting both high Li-ion conductivity and high deformability, as exemplified by Li₃MCl₆-type chlorides. Herein, we optimized the classical force-field (FF) parameters for 36 Li- and Cl-containing compounds to reproduce the results of high-precision first-principles calculations and performed rapid FF molecular dynamics (MD) calculations to determine their Li-ion conductivities. In addition, shear moduli were evaluated by first-principles calculations and used as a deformability index. Li₄Mn₃Cl₁₀ was selected based on its Li-ion conductivity, stiffness, and thermodynamic stability. In accordance with the low calculated shear modulus (11.7 GPa), the cold-pressed compact had a high relative density of 98%, which indicated good deformability. The room-temperature conductivity (3.9 mS cm⁻¹) was similar to that (1.6 mS cm⁻¹) obtained by high-precision first-principles MD calculations. The Li-ion conductivity of synthesized Li₄Mn₃Cl₁₀ (18 µS cm⁻¹) was relatively rather high compared to those of known chloride materials but much lower than the calculated value, which was ascribed to the fact that calculations were performed for the high-temperature phase, whereas synthesis yielded the low-temperature phase. The material screening method greatly increases the speed of material exploration and expands the application possibilities of chloride materials for all-solid-state batteries.     

Nanoindentation responses near single grain boundaries in oxide ceramics

Local mechanical responses near single grain boundaries (GBs) of 9.8 mol% Y₂O₃-stabilized ZrO₂ bicrystals, SrTiO₃ bicrystal, and Al₂O₃ polycrystal were investigated by nanoindentation at room temperature to reveal single GB contributions to the mechanical properties. Contrary to the concept of the Hall–Petch strengthening, the hardness showed negligible variations among grain interiors, GB vicinities, and just on GBs in the samples. Importantly, the hardness may be underestimated owing to GB grooving in thermally etched samples. Despite the negligible change in intrinsic hardness, the transmission electron microscopy observation of the ZrO₂ specimen under impressions revealed dislocation pileups at GBs. These results suggest that single GBs of oxide ceramics prevented dislocation movement but with limited strengthening contributions. This should correspond to the macroscopic Hall–Petch behaviors in oxide ceramics, where the Hall–Petch coefficients normalized by friction stress are significantly smaller than those in metals.     

Two-Step Training: Adjustable Sketch Colourization via Reference Image and Text Tag

Automatic sketch colourization is a highly interestinged topic in the image-generation field. However, due to the absence of texture in sketch images and the lack of training data, existing reference-based methods are ineffective in generating visually pleasant results and cannot edit the colours using text tags. Thus, this paper presents a conditional generative adversarial network (cGAN)-based architecture with a pre-trained convolutional neural network (CNN), reference-based channel-wise attention (RBCA) and self-adaptive multi-layer perceptron (MLP) to tackle this problem. We propose two-step training and spatial latent manipulation to achieve high-quality and colour-adjustable results using reference images and text tags. The superiority of our approach in reference-based colourization is demonstrated through qualitative/quantitative comparisons and user studies with existing network-based methods. We also validate the controllability of the proposed model and discuss the details of our latent manipulation on the basis of experimental results of multi-label manipulation.     

Single-atom microscopy in wide-bandgap nitrides

Wide bandgap III-nitrides, such as cubic boron nitride and wurtzite-type aluminum nitride, are promising systems for optoelectronics. To extend their luminescent properties, we doped single Ce atoms into III-nitride single crystals using reactive flux with a temperature gradient method at high-pressure and high-temperature conditions. To fully understand such properties in a large size-mismatch system, it is critically important to determine the point-defect structures of single dopants, their spatial distribution in three dimensions, and their atomistic dynamics at an atomic level. This review discusses point defect structures and their dynamics in III-nitrides using single-atom-sensitive scanning transmission electron microscopy, and the recent progress in the related field of electron microscopy.