3D X-ray CT and diffusion measurements to assess tortuosity and constrictivity in a sedimentary rock

A high-resolution, three-dimensional (3D) image of the interior of the sedimentary rock was obtained by means of nano-focus X-ray computer tomography (X-ray CT). Using computational methods to analyze the 3D microstructure of the rock, we presented the tortuosity and geometrical constrictivity. We also presented results on the tritiated water (HTO) diffusion tests and a mercury intrusion porosimetry (MIP) test performed on the rock. We have compared these results to understand the dominant parameters that control diffusion of HTO in the present system. These results suggest that the dominant parameters in the present system are not the constrictivity but the tortuosity and the diffusion-accessible porosity. The material considered in this study is the siliceous mudstones sampled from 500 m in depth at the Wakkanai formation around Horonobe underground research center in Hokkaido, Japan

Inhibition of EP2/EP4 signaling abrogates IGF-1R-mediated cancer cell growth : Involvement of protein kinase C-θ activation

Associations between growth factor receptor-mediated cell signaling and cancer cell growth have been previously characterized. Receptors for prostaglandin E2, such as EP2, and EP4, play roles in cancer growth, progression and invasion. Thus, we examined the interactions between EP2/EP4- and IGF-1R-mediated cellular signaling in human pancreatic cancer cells. Selective antagonists against EP2 and EP4 abrogated IGF-1-stimulated cell growth and suppressed MEK/ERK phosphorylation. In subsequent experiments, phospho-antibody arrays indicated increased phosphorylation levels of protein kinase C-θ (PKC-θ) at the Thr538 position following the inhibition of EP2/EP4-mediated signaling. Inhibition of PKC-θ activity impaired cell viability compared with EP2/EP4-antagonized IGF-1-stimulated cells. PKC-θ kinase MAP4K3, which plays a pivotal role in PKC-θ activation, also affected growth signaling in the presence of EP2/EP4 antagonists. Administration of EP2 and EP4 antagonists significantly inhibited the growth of an orthotopic xenograft of IGF-1-secreting pancreatic cancer cells, with increased phospho-PKC-θ and decreased phospho-ERK. Clinico-pathological analyses showed that 17.4% of surgical pancreatic cancer specimens were quadruple-positive for IGF-1R, EP2 (or EP4), MAP4K3, and PKC-θ. These results indicate a novel signaling crosstalk between EP2/EP4 and IGF-1R in cancer cells, and suggest that the MAP4K3-PKC-θ axis is central and could be exploited as a molecular target for cancer therapy

Formation Range, Mechanical Properties and Thermal Stability of Superconducting Zr-Si Amorphous Alloys

New type of refractory metal-metalloid amorphous alloys containing less than 20 at% Si have been found in binary Zr-Si system by a modified melt-spinning technique for high melting point alloys. Specimens are in the form of continuous ribbons of 1-2 mm width and 0.02-0.03 mm thickness. The silicon content in the amorphous range is limited to the range 12 to 24 at%. The Vickers hardness increases from 395 to 495 DPN with increasing silicon content and the tensile strength is of the order of 1400 MPa. Crystallization temperature is the lowest (720 K) at Zr_Si_, increases with decreasing and increasing silicon content and reaches 804 K at Zr_Si_ and 768 K at Zr_Si_. The activation energy for crystallization is in the range 175 to 202 kJ/mol. These amorphous alloys are so ductile that no cracks are observed even after closely contacted bending test. The good ductility remains unchanged for 3.6 ks at temperatures below 650 K. Further, these amorphous alloys exhibit a superconducting transition which occurs very sharply. The superconducting transition temperature (T_c) increases with decreasing silicon content and reaches a maximum value of 3.2 K for Zr_Si_. Thus, the Zr-Si amorphous alloys are a superconductor which possesses the T_c values higher than zirconium metal in addition to high strength combined with good ductility