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This study is dedicated to a comprehensive investigation into the influence of barium strontium titanate (BST) doping on the microstructure, dielectric properties, and electrical behavior of calcium copper titanate (CCTO) ceramics. The research involves a systematic analysis of a series of (1-x) CaCu3Ti4O12 - x Ba0.6Sr0.4TiO3 [(1-x) CCTO/x BST] composite samples, with varying BST ratios (x = 0, x = 0.025, x = 0.075, x = 0.15, and x = 0.2). These composites were synthesized through the solid-state reaction method and subsequently sintered at 1050 °C for a duration of 12 h. The investigation provides detailed insights into microstructural features, dielectric characteristics, and electrical responses, thereby unraveling the intricate correlations between BST content and the resultant material properties. Notably, the sample with x = 0.025 exhibited the highest dielectric constant (εr ≈ 2.71 × 104) and the lowest dielectric loss (tanδ ≈ 0.052) at a frequency of 1 kHz. Furthermore, the optimized composition (x = 0.025) demonstrated exceptional breakdown electric field (Eb ≈ 1284 V/cm) and notable grain boundary resistance (Rgb ≈ 8.8 × 106 Ω). These findings collectively contribute to an enhanced understanding of the impact of BST doping on the distinct characteristics of CCTO ceramics, opening avenues for tailored applications in advanced electronic devices and energy storage systems. [ABSTRACT FROM AUTHOR]

In exploring why American mothers spend more time on care work compared to prior decades while increasingly engaging in paid work, Hays (1997) attributed women's actions to intensive motherhood (IM) ideology. Hays also asserted that women purposedly adhere to IM to resist an increasingly neoliberal market-based society by dedicating time and effort to nurturing children and family life. Here, we undertake a content analysis to take stock of IM literature's evolution in recent decades. Specifically, we examine scholars' treatment of how women adhere to IM, and why and whether women do so in resistance to neoliberalism. We found that while scholars consistently cite and echo Hays (1997) on how women adhere to IM, most depart from Hays (1997) by positing women adhere to live up to an ideal of being a perfect mother due to the pervasive nature of IM. We also found many scholars focus on the possibility of resisting IM ideology itself rather than Hays's (1997) perspective that women employ the ideology to resist neoliberalism. These findings raise questions about how women's agency manifests in the IM context, and concerns about embedded assumptions that limit our understanding of women's realities. Implications are discussed. [ABSTRACT FROM AUTHOR]

This autoethnography represents the first author's journey as a mother and doctoral student researching mothers' experiences in contending with the demands of work and family. Reading across different pockets of empirical motherhood literature (work-family conflict, contemporary motherhood, maternal gatekeeping, and intensive motherhood) I became troubled by how women's realities were reflected. Pushing back against traditional methods that endorse separating my researcher identity from my maternal self, I draw on autoethnographic method to dialogue with this literature. This approach empowers me to speak out as a novice scholar uncomfortable with aspects of literature, while also navigating training in the use of traditional methods that often provide a directive to separate academic and personal identities. Importantly, doing so enables me to identify powerful insights about limitations in the literature, and how specific pockets of research can adversely affect the broader motherhood literature. [ABSTRACT FROM AUTHOR]

CaCu3Ti4O12 (CCTO) ceramics have been widely demonstrated due to their high dielectric constant and are considered potential materials for capacitor applications. However, its high dielectric loss (tanδ), which is greater than 0.1, makes it unsuitable for a lot of uses. Generally, CCTO doped with Ni ions exhibits low nonlinear properties and a high tanδ. In this work, CaCu2.9Ni0.1Ti4O12 (with x = 0/0.1/0.2) ceramics were synthesized by a semi-wet route. Significantly, the CaCu2.8Ni0.2Ti4O12 (Ni02) ceramic revealed an enhancement in breakdown electric voltage (Eb≈ 4208 V/cm) and nonlinear coefficient (α ≈ 7.69) with a considerably decrease in dielectric loss (tanδ ≈ 0.017). The mean grain size for Ni02 ceramic decreased from 6.15 to 2.23 μm. Density increased at first from 91.05 to 92.88% and then decreased by 89.6% with grain size reduction. The decrease in its mean grain size was attributed to the incorporation of Ni ions into Ti sites, as explained by DRX, EDS, and Raman results. The band gap energy increased from 2.25 eV for undoped CCTO ceramic to 3.54 eV for Ni02 ceramic. Additionally, all the ceramic samples present a high dielectric constant (ε) in the range of 104–105. According to the complex impedance spectroscopy results, the electrically heterogeneous CCTO microstructure is responsible for the high dielectric response. Moreover, the enhancement of dielectric and electric properties is attributed to the grain boundary effect. [ABSTRACT FROM AUTHOR]

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/β (GSK-3 α/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

Colossal permittivity of CaCu3Ti4O12 (CCTO) makes it a very interesting candidate for capacitor applications. To improve its properties, an innovative physical method based on a pulsed non-thermal micro-plasma treatment was set up to realize the coating of CCTO's grains (core) with silicon oxide (shell). This method is adapted to control the thickness and homogeneity of the shell, which will allow a better control of grain–grain boundary interfaces and improve the properties of this material. Best result is obtained for the set of gas mixture: Ar/O2/hexamethyldisiloxane (HMDSO) = 2028 N cm3 min−1/7.84 N cm3 min−1/523 mg h−1, respectively, in plasma with a shell thickness of 50 nm. This study offers a new opportunity to quickly synthetize core–shell materials with a dry technique and without almost no secondary product resulting from the chemical reaction because it is in the gaseous state. A complete analysis of the plasma by optical emission spectroscopy in the UV-visible range shows that HMDSO molecules are totally dissociated in atomic (Si, C, and O) or simple radical species (C2 and CH) in the plasma phase. In addition, several thermometer species (OH°, CH, CN, N2, and N2+) are used to estimate excitation temperatures of the plasma (Trot, Tvib, and Te = 300 K, 2400–3700 K, and 5.3 eV, respectively) that clearly shows the non-equilibrium character and the efficiency of this plasma. [ABSTRACT FROM AUTHOR]

Aging of the population in developed countries is an important challenge to overcome. Robots have a role to play to offer solutions to old and dependent persons and also to their families and carers. We investigated low-cost high-tech robotics in order to offer affordable mobile robots that could be used in the context of ambient assisted living (AAL). We used a bottom–up approach and tried different technical solutions in order to propose an efficient prototype. Results of this experimental work are presented in the first part of this paper. From the different experiments we carried out, we felt the need to use a top–down approach that could be used to develop such robots and also any system that requires the use of mechanical, electronic, and software components. In the second part of this paper, we present the X-methodology and try to show its use in our AAL context.