Characterization of Mechanical Properties for Creep-fatigued Ferritic Heat-resisting Steel by Nano-indentation

AbstractCreep-fatigue test was conducted for a ferritic heat-resisting steel that contained 12mass%chromium and 2mass% tungsten. The creep-fatigue fracture originated from prior austenite grain boundaries. Subgrains neighboring the prior austenite grain boundaries became coarse during creep-fatigue testing. Nano-indentation tests were performed on the coarse subgrains neighboring grain boundaries and finer subgrains inner grains. As the results, the nano scale-hardness of the coarse subgrains were markedly lower than those of the finer subgrains inner grains. Therefore, it is suggested that the coarse subgrains neighboring grain boundaries play an important role of creep-fatigue fracture mechanism

Analysis of tangential contact damping mechanism by direct observation using X-ray computed tomography

The damping of metal contact surfaces considerably influences the dynamic characteristics of machines. However, the contact damping mechanism has not yet been sufficiently clarified because it is difficult to directly observe metal–metal contact surfaces. In this study, the deformation of the metal surface asperity caused by a tangential load was analyzed using a combination of X-ray computed tomography and finite element method (FEM) simulations. The FEM simulation considering the elastic–plastic deformation and slip reproduced the experimental results well. The contribution of the elastic–plastic deformation and slip of asperities to contact damping was discussed using the developed simulation

Electron-Diffraction Investigation of the Hexafluorides of Tungsten, Osmium, Iridium, Uranium, Neptunium, and Plutonium

An electron‐diffraction investigation has been made by the sector–microphotometer method on WF_6, OsF_6, IrF_6, UF_6, NpF_6, and PuF_6. The photographs of all these compounds reflect a phase shift which if not accounted for leads to asymmetric structures for the molecules. It sets in at smaller values of s=4πλ^(−1) sin (θ/2) the heavier the molecule and the greater the electron wavelength. There is good evidence for the symmetrical octahedral structure of all the compounds. The metal–fluorine distances were found to be 1.833 Å (W–F), 1.831 Å (Os–F), 1.830 Å(Ir–F), 1.996 Å (U–F), 1.981 Å (Np–F), and 1.971 Å (Pu–F), with estimated limits of error of ±0.008 Å except for ±0.010 Å for Pu–F

Vertically stacked graphene tunnel junction with structured water barrier

We report a vertically stacked graphene tunnel junction with an atomically thin insulating layer for novel function devices. The insulating water layer sandwiched between graphene samples as a tunnel barrier which is fabricated through deionized (DI) water treatment of epitaxial graphene. Two graphene samples fabricated by SiC thermal decomposition are directly bonded to each other in a face-to-face manner. Vertically stacked graphene samples without DI water treated formed an ohmic junction. By inserting the structured water layer as tunnel barrier, the stacked junction exhibits Direct tunneling (DT) characteristics in a low-electric-field regime and Fowler-Nordheim tunneling (FNT) characteristics in a high-electric-field regime. The thickness of the structured water layer is estimated to be 0.28 nm by fitting the FNT formula. The very thin structured water layer is stable as tunnel barrier on epitaxial graphene for diode devices, which will have a widely application in electronic devices

Modulating effect of the PI3-kinase inhibitor LY294002 on cisplatin in human pancreatic cancer cells

<p>Abstract</p> <p>Background</p> <p>Chemoresistance is a serious problem in pancreatic cancer, but the mechanism of resistance and strategies against the resistance have not been elucidated. We examined the potential of the phosphatidylinositol 3-kinase (PI3K)/Akt inhibitor LY294002 to enhance the anti-tumor effect of cisplatin and investigated the mechanism of chemoresistance in pancreatic cancer cells using a combination therapy of cisplatin and LY294002, both <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>Cisplatin and LY294002, individually or in combination, were given to AsPC-1 and PANC-1 cell lines. Tumor growth, DNA fragments, and Akt phosphorylation were examined <it>in vitro</it>. To examine the therapeutic effect of cisplatin and LY294002, individually or combination an AsPC-1 tumor xenograft model was prepared for <it>in vivo </it>study.</p> <p>Results</p> <p>Cisplatin induced growth inhibition and Akt phosphorylation in pancreatic cancer cells. LY294002 also inhibited cell proliferation but without showing Akt phosphorylation. However, the combination therapy markedly increased cleavage of caspase-3 and cytoplasmic histone-associated DNA fragments compared to the results with cisplatin alone. In the <it>in vivo </it>study, blocking the PI3K/Akt cascade with LY294002 increased the efficacy of cisplatin-induced inhibition of tumor growth in nude mice, suppressing half the tumor growth with cisplatin alone. There were no detectable side effects in mice treated with combination therapy.</p> <p>Conclusion</p> <p>Our studies suggest that the PI3K/Akt pathway plays an important role in cisplatin resistance of pancreatic cancer cells. The augmentation of cisplatin with PI3K/Akt inhibitor may resolve the chemoresistance problem of cisplatin, and this might be a plausible strategy for achieving tolerance for chemotherapeutic agents in pancreatic cancer therapy.</p

Exercise Therapy for Management of Type 2 Diabetes Mellitus: Superior Efficacy of Activity Monitors over Pedometers

We compared the efficacy of activity monitor (which displays exercise intensity and number of steps) versus that of pedometer in exercise therapy for patients with type 2 diabetes. The study subjects were divided into the activity monitor group (n=92) and pedometer group (n=95). The primary goal was improvement in hemoglobin A1c (HbA1c). The exercise target was set at 8,000 steps/day and 20 minutes of moderate-intensity exercise (≥3.5 metabolic equivalents). The activity monitor is equipped with a triple-axis accelerometer sensor capable of measuring medium-intensity walking duration, number of steps, walking distance, calorie consumption, and total calorie consumption. The pedometer counts the number of steps. Blood samples for laboratory tests were obtained during the visits. The first examination was conducted at the start of the study and repeated at 2 and 6 months. A significant difference in the decrease in HbA1c level was observed between the two groups at 2 months. The results suggest that the use of activity level monitor that displays information on exercise intensity, in addition to the number of steps, is useful in exercise therapy as it enhances the concept of exercise therapy and promotes lowering of HbA1c in diabetic patients