Structural and electronic impact of SrTiO3 substrate on TiO2 thin films

We demonstrate that the atomic structures, electronic states, and bonding nature of the interface between SrTiO₃ substrate and anatase TiO₂ thin films could be related and technologically manipulated at the atomic level. Applying advanced transmission electron microscopy, the grown anatase TiO₂ thin films are found to make a clean and direct contact to the SrTiO₃ substrates in an epitaxial, coherent, and atomically abrupt way. The atomic-resolution microscopic images reveal that the interface comprises SrO-terminated SrTiO₃ and Ti-terminated TiO₂ with the interfacial Ti of TiO₂ sitting above the hollow site, which is confirmed theoretically to be the most energetically favorable. Quantitatively, the first-principles calculations predict that the oxygen sublattice at the interface undergoes a notable reconstruction, i.e., the interfacial O atoms of TiO₂ are displaced largely toward the SrO plane of the SrTiO₃, flattening the originally zigzag TiO₂ atomic chains. Consequently, the interfacial layers suffer a remarkable modification in the charge accumulation and also a deviation in the density of states from their bulk counterparts, indicating that the substrate can have an impact on the deposited thin films electronically. Using several analytic methods, the SrTiO₃/TiO₂ interface is found to take on a metallic nature, and the interfacial bonding is determined to be of a mixed covalent and ionic character. This combined experimental and theoretical investigation gains insight into the complex atomic and electronic structures of the buried interface, which are fundamental for relating the atomic-scale structures to their properties on a quantum level.     

In Vitro Tumor Cell-Binding Assay to Select High-Binding Antibody and Predict Therapy Response for Personalized 64Cu-Intraperitoneal Radioimmunotherapy against Peritoneal Dissemination of Pancreatic Cancer: A Feasibility Study

Peritoneal dissemination of pancreatic cancer has a poor prognosis. We have reported that intraperitoneal radioimmunotherapy using a ⁶⁴Cu-labeled antibody (⁶⁴Cu-ipRIT) is a promising adjuvant therapy option to prevent this complication. To achieve personalized ⁶⁴Cu-ipRIT, we developed a new in vitro tumor cell-binding assay (⁶⁴Cu-TuBA) system with a panel containing nine candidate ⁶⁴Cu-labeled antibodies targeting seven antigens (EGFR, HER2, HER3, TfR, EpCAM, LAT1, and CD98), which are reportedly overexpressed in patients with pancreatic cancer. We investigated the feasibility of ⁶⁴Cu-TuBA to select the highest-binding antibody for individual cancer cell lines and predict the treatment response in vivo for ⁶⁴Cu-ipRIT. ⁶⁴Cu-TuBA was performed using six human pancreatic cancer cell lines. For three cell lines, an in vivo treatment study was performed with ⁶⁴Cu-ipRIT using high-, middle-, or low-binding antibodies in each peritoneal dissemination mouse model. The high-binding antibodies significantly prolonged survival in each mouse model, while low-and middle-binding antibodies were ineffective. There was a correlation between in vitro cell binding and in vivo therapeutic efficacy. Our findings suggest that ⁶⁴Cu-TuBA can be used for patient selection to enable personalized ⁶⁴Cu-ipRIT. Tumor cells isolated from surgically resected tumor tissues would be suitable for analysis with the ⁶⁴Cu-TuBA system in future clinical studies.     

Effect of Graphite Nodule Diameter on Water Embrittlement of Austempered Ductile Iron

DuctileironwasdevelopedbyMorrogh[1]in 1940s.Theappearanceofaustemperedductileiron (ADI)in1970sessentiallyaffectedthemetallurgical researchofductileiron[2,3].ADIhasverygood properties[4-15].Itisproducedbyaustemperingcon ventionalductileiron,andthemicrostr…     

The role of wingbeat frequency and amplitude in flight power

Body-mounted accelerometers provide a new prospect for estimating power use in flying birds, as the signal varies with the two major kinematic determinants of aerodynamic power: wingbeat frequency and amplitude. Yet wingbeat frequency is sometimes used as a proxy for power output in isolation. There is, therefore, a need to understand which kinematic parameter birds vary and whether this is predicted by flight mode (e.g. accelerating, ascending/descending flight), speed or morphology. We investigate this using high-frequency acceleration data from (i) 14 species flying in the wild, (ii) two species flying in controlled conditions in a wind tunnel and (iii) a review of experimental and field studies. While wingbeat frequency and amplitude were positively correlated, R² values were generally low, supporting the idea that parameters can vary independently. Indeed, birds were more likely to modulate wingbeat amplitude for more energy-demanding flight modes, including climbing and take-off. Nonetheless, the striking variability, even within species and flight types, highlights the complexity of describing the kinematic relationships, which appear sensitive to both the biological and physical context. Notwithstanding this, acceleration metrics that incorporate both kinematic parameters should be more robust proxies for power than wingbeat frequency alone.     

Defect structures and dopant solution states of Hf-doped Si3N4 ceramics

Transition-metal-doped silicon nitride ceramics have attracted much attention as gate materials for semiconductors because of their electrical properties as well as chemical and thermal stability. The present study aims to clarify the defect structures of Hf-doped β-Si₃N₄ by theoretical calculations and scanning transmission electron microscopy (STEM). First-principles calculations based on a hybrid functional method were performed. It was found that Hf dopants are mainly substituted for the Si sites and can be occasionally located at interstitial sites in the lattice of β-Si₃N₄. The substitution sites of Hf dopants predicted by the first-principles calculations were also confirmed by the high-resolution STEM images.     

Carbon Nitride Loaded with an Ultrafine,Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO₃ and BaLa₄Ti₄O₁₅.     

Effect of display of YOLO’s object recognition results to HMD for an operator controlling a mobile robot

Artificial Life and Robotics - An operator feels a burden when he/she controls a rescue robot remotely because he/she has to keep watching camera images to find the target object. We think that...     

Improvement of steady-state performance for discrete-valued input control with an integrator utilizing feedback control of integrated value of input

In this study, we considered the regulator problem for discrete-valued input control with an integrator. In some cases, the state does not converge to the origin in the discrete-valued input control when the plant possesses an integrator. Therefore, a method that adds minor feedback control to the integrated value of the input was proposed. However, the effect of the feedback control of the integrated value of the input was not theoretically interpreted, and the feedback gain for the state of the integrated value of the input was designed with trial and error. Herein, we clarify the effect of feedback control on the integrated value of the input. Furthermore, we reveal that the trade-off between the steady-state and transient performances is controlled by one parameter, that is, the feedback gain for the integrated value of the input.     

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.