Small crack behavior and fracture of nickel-based superalloy under ultrasonic fatigue

Fracture and small crack behavior in the very high cycle domain of 10⁹ cycles were investigated with a nickel-based superalloy under ultrasonic fatigue in ambient air at room temperature. The influence of ultrasonic frequency is examined by comparing the results with those in conventional low frequency fatigue. It is found that fatigue strength increases as frequency is raised up to 19.5 kHz and the most of fatigue life is consumed in nucleating and propagating small cracks up to 100 μm. Transition of fracture mode from transgranular ductile fracture to cleavage-dominated fracture occurs beyond a critical stress intensity factor range of approximately , leading to the catastrophic failure under ultrasonic fatigue.     

Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire

The spin transfer torque is essential for electrical magnetization switching. When a magnetic domain wall is driven by an electric current through an adiabatic spin torque, the theory predicts a threshold current even for a perfect wire without any extrinsic pinning. The experimental confirmation of this 'intrinsic pinning', however, has long been missing. Here, we give evidence that this intrinsic pinning determines the threshold, and thus that the adiabatic spin torque dominates the domain wall motion in a perpendicularly magnetized Co/Ni nanowire. The intrinsic nature manifests itself both in the field-independent threshold current and in the presence of its minimum on tuning the wire width. The demonstrated domain wall motion purely due to the adiabatic spin torque will serve to achieve robust operation and low energy consumption in spintronic devices.     

Modeling of ion-bombardment damage on Si surfaces for in-line analysis

Structures and mechanism of ion-bombardment damage on silicon wafers exposed to plasma were investigated comprehensively. By using molecular dynamics simulations high-resolution transmission electron microscopy, and composition analysis by high-resolution Rutherford backscattering spectroscopy, features such as gradual transition from the SiO₂ surface to the Si substrate and interface roughness were addressed. On the basis of these findings, the optical model that addresses the characteristics of plasma-damaged Si surfaces is given for ellipsometric analysis. The proposed model includes an interface layer modeled as a mixture of SiO₂ and Si phases. A part of the interface layer could not be removed by wet-etching, signifying the distinct features of the interface layer that are difficult to remove. The proposed model is anticipated to be practical for in-line monitoring of plasma-induced damage.     

Character animation creation using hand-drawn sketches

To create a character animation, a 3D character model is often needed. However, since humanlike characters are not rigid bodies, to deform the character model to fit each animation frame is tedious work. Therefore, we propose an easy-to-use method for creating a set of consistent 3D character models from some hand-drawn sketches while keeping the projected silhouettes and features of the created models consistent with the input sketches. Since the character models possess vertexwise correspondences, they can be used for frame-consistent texture mapping or for making character animations. In our system, the user only needs to annotate the correspondence of the features among the input-vector-based sketches; the remaining processes are all performed automatically.     

Human Chorionic Villous Differentiation and Placental Development

In humans, the placenta provides the only fetomaternal connection and is essential for establishing a pregnancy as well as fetal well-being. Additionally, it allows maternal physiological adaptation and embryonic immunological acceptance, support, and nutrition. The placenta is derived from extra-embryonic tissues that develop rapidly and dynamically in the first weeks of pregnancy. It is primarily composed of trophoblasts that differentiate into villi, stromal cells, macrophages, and fetal endothelial cells (FEC). Placental differentiation may be closely related to perinatal diseases, including fetal growth retardation (FGR) and hypertensive disorders of pregnancy (HDP), and miscarriage. There are limited findings regarding human chorionic villous differentiation and placental development because conducting in vivo studies is extremely difficult. Placental tissue varies widely among species. Thus, experimental animal findings are difficult to apply to humans. Early villous differentiation is difficult to study due to the small tissue size; however, a detailed analysis can potentially elucidate perinatal disease causes or help develop novel therapies. Artificial induction of early villous differentiation using human embryonic stem (ES) cells/induced pluripotent stem (iPS) cells was attempted, producing normally differentiated villi that can be used for interventional/invasive research. Here, we summarized and correlated early villous differentiation findings and discussed clinical diseases.     

Uterine Deletion of Bmal1 Impairs Placental Vascularization and Induces Intrauterine Fetal Death in Mice

Recently, it was demonstrated that the expression of BMAL1 was decreased in the endometrium of women suffering from recurrent spontaneous abortion. To investigate the pathological roles of uterine clock genes during pregnancy, we produced conditional deletion of uterine Bmal1 (cKO) mice and found that cKO mice could receive embryo implantation but not sustain pregnancy. Gene ontology analysis of microarray suggested that uterine NK (uNK) cell function was suppressed in cKO mice. Histological examination revealed the poor formation of maternal vascular spaces in the placenta. In contrast to WT mice, uNK cells in the spongiotrophoblast layer, where maternal uNK cells are directly in contact with fetal trophoblast, hardly expressed an immunosuppressive NK marker, CD161, in cKO mice. By progesterone supplementation, pregnancy could be sustained until the end of pregnancy in some cKO mice. Although this treatment did not improve the structural abnormalities of the placenta, it recruited CD161-positive NK cells into the spongiotrophoblast layer in cKO mice. These findings indicate that the uterine clock system may be critical for pregnancy maintenance after embryo implantation.     

Unkeito Suppresses RANKL-Mediated Osteoclastogenesis via the Blimp1–Bcl6 and NF-κB Signaling Pathways and Enhancing Osteoclast Apoptosis

Osteoporosis is a common bone disease, particularly in menopausal women. Herein, we screened four Kampo medicines (Unkeito (UKT), Kamishoyosan (KSS), Kamikihito (KKT), and Ninjinyoeito (NYT)), frequently used to treat menopausal syndromes, for their effects on receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclast differentiation in RAW 264 cells. Considering that UKT exhibited the most potent effect, we examined its effect on RANKL-induced osteoclastogenesis, the induction of osteoclast apoptosis, and the mechanisms underlying its effects. UKT inhibits RANKL-induced osteoclast differentiation in the early stage and decreases osteoclast-related genes, including tartrate-resistant acid phosphatase (Trap), dendritic cell-specific transmembrane protein (Dcstamp), matrix metalloproteinase-9 (Mmp9), and cathepsin K (Ctsk). Specifically, UKT inhibits the nuclear factor of activated T cells 1 (NFATc1), which is essential for osteoclastogenesis. UKT increases Bcl6, which antagonizes NFATc1 and Dc-stamp, thereby blocking the progression of osteoclasts to maturation. UKT also decreased nuclear translocation by downregulating the activity of p65/NF-κB. In addition, UKT enhances mononuclear osteoclast apoptosis via activation of caspase-3. Herein, we demonstrate that UKT suppresses RANKL-mediated osteoclastogenesis via the Blimp1–Bcl6 and NF-κB signaling pathways and enhances mononuclear osteoclast apoptosis. Furthermore, UKT prevents bone loss in OVX mice. Thus, UKT might be a potential therapeutic agent for postmenopausal osteoporosis.     

Up?Scalable Fabrication of -SnO2 with Multifunctional Interface for High Performance Perovskite Solar Modules

Tin dioxide -(SnO2) has been demonstrated as one of the promising electron transport layers for highefficiency perovskite solar cells (PSCs). However, scalable ...