Thermoelectric properties of layered oxyselenides La1–xSrxCuOSe (x = 0 to 0.2)

Thermoelectric properties of layered oxyselenides La1–xSrxCuOSe (x = 0.00 to 0.20) were investigated to evaluate the potential as thermoelectric material. Temperature dependence of the electrical conductivity and Seebeck coefficient measured in a temperature range of 373 to 673 K indicated that nondoped LaCuOSe was a p-type degenerate semiconductor due to Cu vacancies, while Sr-doped materials with x = 0.05 to 0.20 were p-type metals. The electrical conductivity increased and Seebeck coefficient decreased with increasing Sr concentration up to x = 0.10 in La1–xSrxCuOSe, suggesting that the effective hole carriers increase with increasing Sr content up to x = 0.10. Thermoelectric power factors were drastically enhanced by the Sr doping, and the value reached 1.0–1.4×10–4 W m–1 K–2 for La0.95Sr0.05CuOSe. Thermal conductivities measured for the materials with x = 0.00 and 0.05 were 2.1 W m–1 K–1 and 2.3 W m–1 K–1 at room temperature, respectively. These results lead to an estimation of Z value of 4.4×10–5 K–1 for La0.95Sr0.05CuOSe

Thermoelectric properties of delafossite-type layered oxides AgIn1–xSnxO2

The thermoelectric properties of delafossite-type layered oxides AgIn1–xSnxO2 that consist of alternating layers of Ag and In1–xSnxO2 were investigated to elucidate their potential as a thermoelectric material. Polycrystalline materials of the AgIn1–xSnxO2 were prepared by a cation exchange reaction between NaIn1–xSnxO2 and AgCl. The solubility limit of the Sn atoms on the In sites was approximately x=0.05. The electrical conductivity and Seebeck coefficient were measured between 373 and 673 K in air. Undoped AgInO2 was an n-type semiconductor with conductivities of 10–4–10–2 –1 cm–1, and the electron carriers were generated via the formation of oxygen vacancies. AgIn0.95Sn0.05O2 was an n-type degenerate semiconductor with conductivities of 100–101 –1 cm–1 where the Sn atoms acted as electron donors. This drastic increase in the electrical conductivity increased the thermoelectric power factor by approximately two orders of magnitude to 10–6–10–5 W m–1 K–2

Thermoelectric properties of delafossite-type layered oxides AgIn1–xSnxO2

The thermoelectric properties of delafossite-type layered oxides AgIn1–xSnxO2 that consist of alternating layers of Ag and In1–xSnxO2 were investigated to elucidate their potential as a thermoelectric material. Polycrystalline materials of the AgIn1–xSnxO2 were prepared by a cation exchange reaction between NaIn1–xSnxO2 and AgCl. The solubility limit of the Sn atoms on the In sites was approximately x=0.05. The electrical conductivity and Seebeck coefficient were measured between 373 and 673 K in air. Undoped AgInO2 was an n-type semiconductor with conductivities of 10–4–10–2 –1 cm–1, and the electron carriers were generated via the formation of oxygen vacancies. AgIn0.95Sn0.05O2 was an n-type degenerate semiconductor with conductivities of 100–101 –1 cm–1 where the Sn atoms acted as electron donors. This drastic increase in the electrical conductivity increased the thermoelectric power factor by approximately two orders of magnitude to 10–6–10–5 W m–1 K–2

Event-Driven Particle Filter for Tracking Irregularly Moving Objects

Conventional object tracking techniques that use general-purpose cameras and particle filters find it difficult to track irregularly and rapidly moving objects. To track an irregularly moving object without losing sight, quickly measuring the position of the object is necessary. In this study, we used a fast-response event-based camera, which is a bioinspired camera that produces a spiking output. We propose an event-driven particle filter that performs processing in response to the input from an event-based camera. Our proposed method was evaluated by presenting an event-based camera with a rectangular motion pattern that combines periodic and constant-velocity motions at various speeds. The experimental results demonstrated that our proposed method could track objects in a test video.The 2023 International Conference on Artificial Life and Robotics (ICAROB 2023), February 9-12, 2023, on line, Oita, Japanconference pape

Adenosine triphosphate induces amorphous aggregation of amyloid β by increasing Aβ dynamics

アルツハイマー病に関係するアミロイドβ1分子の凝集動態を観察. 京都大学プレスリリース. 2024-04-23.Amyloid β (Aβ) aggregates into two distinct fibril and amorphous forms in the brains of patients with Alzheimer’s disease. Adenosine triphosphate (ATP) is a biological hydrotrope that causes Aβ to form amorphous aggregates and inhibit fibril formation at physiological concentrations. Based on diffracted X-ray blinking (DXB) analysis, the dynamics of Aβ significantly increased immediately after ATP was added compared to those in the absence and presence of ADP and AMP, and the effect diminished after 30 min as the aggregates formed. In the presence of ATP, the β-sheet content of Aβ gradually increased from the beginning, and in the absence of ATP, the content increased rapidly after 180 min incubation, as revealed by a time-dependent thioflavin T fluorescence assay. Images of an atomic force microscope revealed that ATP induces the formation of amorphous aggregates with an average diameter of less than 100 nm, preventing fibrillar formation during 4 days of incubation at 37℃. ATP may induce amorphous aggregation by increasing the dynamics of Aβ, and as a result, the other aggregation pathway is omitted. Our results also suggest that DXB analysis is a useful method to evaluate the inhibitory effect of fibrillar formation

The Catalytic Conversion of 1,2-Propandiol to Propanal on FSM-16 Molded by Wet-Treatment and Pressurization

The catalytic conversion of 1,2-propandiol to propanal is examined using FSM-16 particles (0.85－1.70 mm) molded by wet-treatment and pressurization. When FSM-16 was molded with 0.6 g of pressurization and supplied to the catalytic conversion of 1,2-propandiol at 673 K, this system resulted in a 94.8% conversion of 1,2-propandiol and 90.5% selectivity to propanal at 0.25 h on-stream, which was the maximum amount of activity. However, at 4.50 h on-stream, the activity decreased extremely to deactivation 19.9% conversion of 1,2-propandiol and 84.7% selectivity to propanal. In contrast, when FSM-16 molded with wet-treatment (0.15 g) was used for the conversion at 573 K, activity was greatly increased and stable 98.6% conversion of 1,2-propandiol and 56.2% selectivity to propanal at 0.25 h on-stream followed by 91.9% and 52.5%, respectively, at 4.50 h on-stream. The hexagonal structure of FSM-16 was suggested to have contributed to the suitable conversion of 1,2-propandiol to propanal

<i>Dpysl4</i> Is Involved in Tooth Germ Morphogenesis through Growth Regulation, Polarization and Differentiation of Dental Epithelial Cells

Dihydropyrimidinase-related protein 4 (Dpysl4) is a known regulator of hippocampal neuron development. Here, we report that Dpysl4 is involved in growth regulation, polarization and differentiation of dental epithelial cells during tooth germ morphogenesis. A reduction in Dpysl4 gene expression in the tooth germ produced a loss of ameloblasts, resulting in the decrease of synthesis and secretion of enamel. The inhibition of Dpysl4 gene expression led to promotion of cell proliferation of inner enamel epithelial cells and inhibition of the differentiation of these cells into pre-ameloblasts, which was confirmed by analyzing cell polarization, columnar cell structure formation and the expression of ameloblast marker genes. By contrast, overexpression of Dpysl4 in dental epithelial cells induces inhibition of growth and increases the expression of the inner enamel epithelial cell marker gene, Msx2. These findings suggest that Dpysl4 plays essential roles in tooth germ morphogenesis through the regulation of dental epithelial cell proliferation, cell polarization and differentiation

Acidic Properties of Various Silica Catalysts Doped with Chromium for the Oxidative Dehydrogenation of Isobutane to Isobutene

Although previous researchers have found that FSM-16 (#16 Folded Sheet Mesoporous material) doped with chromium and related Cr-doped silica catalysts has shown great activity for the oxidative dehydrogenation of isobutane to isobutene, information on the nature of these catalysts is insufficient. For this study, three types of Cr-doped silica catalysts were prepared by applying the template ion exchange method. CrOx/FSM-16 and CrOx/SiO2 were used as references. These catalysts were used for oxidative dehydrogenation, which was then characterized via various techniques. The most active catalyst was Cr-doped silica, which did not have the hexagonal structure that is characteristic of mesoporous FSM-16. Various characterizations showed that the catalytic activity of the Cr-species, stemmed from a weak acidic nature and a redox nature that originated from the combination of silicate and a Cr cation, as opposed to the hexagonal structure and strong acidic nature of FSM-16

Effects of Acidic Properties of FSM-16 on the Catalytic Conversion of 1,2-Propandiol in the Presence and Absence of Hydrogen

We have earlier showed how the catalytic conversion of 1,2-propandiol to propanal using FSM-16 (#16 folded sheets of mesoporous materials) when molded by wet treatment proceeded more favorably than when using FSM-16 molded by pressurization, while no comparison using other typical acidic catalysts and no examination of the acidic properties of FSM-16 was carried out. In the present study, the conversion using FSM-16 molded by wet treatment and pressurization was compared with that obtained by using typical acidic catalysts such as SiW12O40/SiO2 and MCM-41 (#41 of Mobil Composition of Matter) together with amorphous SiO2. Among these catalysts, FSM-16 molded by wet treatment showed the most suitable catalytic activity. In order to examine the effect of the molding procedure for FSM-16 on its structural and acidic properties, FSM-16 molded by both methods was examined using NH3-TPD, in situ FT-IR using NH3 as a probe molecule, and Hammett indicators together with XRD and TEM. According to Zaitsev's rule, the present conversion should afford acetone rather than propanal, which indicates that it would proceed via hydro cracking. Therefore, the conversion of 1,2-propandiol using FSM-16 was also examined in the presence and absence of hydrogen. Furthermore, hydration reactions of 1- and 2-propanol when using FMS-16 were examined. Based on the results obtained from this investigation, it was concluded that the conversion using a more acidic FSM-16 molded by wet treatment proceeded through dehydration rather than through hydro cracking