Electric field effects on magnetism in metals have attracted widespread attention, but the microscopic mechanism is still controversial. We experimentally show the relevancy between the electric field effect on magnetism and on the electronic structure in Pt in a ferromagnetic state using element-specific measurements: x-ray magnetic circular dichroism (XMCD) and x-ray absorption spectroscopy (XAS). Electric fields are applied to the surface of ultrathin metallic Pt, in which a magnetic moment is induced by the ferromagnetic proximity effect resulting from a Co underlayer. XMCD and XAS measurements performed under the application of electric fields reveal that both the spin and orbital magnetic moments of Pt atoms are electrically modulated, which can be explained not only by the electric-field-induced shift of the Fermi level but also by the change in the orbital hybridizations.
The anti-tumor effect of a selective cyclooxygenase (COX)-2 inhibitor, JTE-522, was examined with the human head and neck squamous cell carcinoma cell line KB. KB cells do not produce prostaglandin (PG)-E2. In vitro, JTE-522 induced an increase of G1 phase-arrested cells, suppression of platelet-derived growth factor (PDGF) production and inhibition of telomerase activity. No cytotoxic effect was detected. In vivo, the growth of the tumor xenografted into nude mice was significantly suppressed by JTE-522. Suppression of angiogenesis at the periphery of the tumor, increase of G1-arrested cells and suppression of telomerase activity were observed, together with an increase of apoptotic cell death in the tumor. Immunological enhancement did not play a role. We concluded that the anti-tumor effect of JTE-522 was caused by anti-angiogenesis action, cell cycle arrest and inhibition of telomerase activity of the tumor cells. These combined effects might induce apoptosis.Key words: Head and neck squamous carcinoma cells -Selective cyclooxgenase-2 inhibitor -Cell cycle arrest -Anti-angiogenesis -Telomerase activity inhibition Nonsteroidal anti-inflammatory drugs (NSAIDs) are promising candidates for chemopreventive agents active against the development of cancers in the colon, the bladder, the mammary gland, the skin, and the liver.
;Primary roots of cucumber seedlings showed positive hydrotropism when exposed to a moisture gradient and rotated on a two-axis clinostat. To examine the role of auxin in the differential growth of the hydrotropically responding roots, we first examined the expression of auxin-inducible genes, CS-AUX/IAAs, in cucumber roots. After auxin starvation, mRNA levels of CS-IAA1 and CS-IAA3 decreased in the roots. Applying auxin to the auxin-starved roots resulted in accumulation of CS-IAA1 and CS-IAA3 mRNA. The level of expression of these genes increased when the auxin concentration was increased. CS-IAA1 mRNA accumulated in response to 10 -8 M auxin, and the level increased further, depending on the dose. Auxin starvation did not result in a decrease in the level of CS-IAA2 mRNA; however, adding exogenous auxin at concentrations higher than 10 -7 M increased its accumulation. In the primary roots responding hydrotropically or gravitropically, CS-IAA1 expression was greater on the concave side of the curving roots than on the convex side. The difference could be detected 30 min following stimulation by gravity or a moisture gradient, and that difference increased with time. These results support the idea that asymmetry of localization of auxin is associated with differential growth in hydrotropically responding roots.
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