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Background: Mouse embryos are cup shaped, but most nonrodent eutherian embryos are disk shaped. Extraembryonic ectoderm (ExEc), which may have essential roles in anterior–posterior (A-P) axis formation in mouse embryos, does not develop in many eutherian embryos. To assess A-P axis formation in eutherians, comparative analyses were made on rabbit, porcine, and Suncus embryos. Results: All embryos examined expressed Nodal initially throughout epiblast and visceral endoderm; its expression became restricted to the posterior region before gastrulation. Anterior visceral endoderm (AVE) genes were expressed in Otx2-positive visceral endoderm, with Dkk1 expression being most anterior. The mouse pattern of AVE formation was conserved in rabbit embryos, but had diverged in porcine and Suncus embryos. No structure that was molecularly equivalent to Bmp-positive ExEc, existed in rabbit or pig embryos. In Suncus embryos, A-P axis was determined at prehatching stage, and these embryos attached to uterine wall at future posterior side. Conclusions: Nodal, but not Bmp, functions in epiblast and visceral endoderm development may be conserved in eutherians. AVE functions may also be conserved, but the pattern of its formation has diverged among eutherians. Roles of BMP and NODAL gradients in AVE formation seem to have been established in a subset of rodents. [ABSTRACT FROM AUTHOR]

A memory effect of in-plane-gated field-effect transistors (IPGFETs) has been observed on hydrogen-terminated and oxygen-terminated diamond surfaces. The hysteresis characteristics are achieved by the hole traps in the oxygen-terminated surface of the IPGFETs where the threshold voltage shift by the gate voltage sweep is confirmed in the Id–Vg characteristics. This feature is observed under light illumination, and depends on the radiant flux density. The hysteresis characteristics become very small under the condition of no light irradiation at room temperature. It is assumed that carrier trap sites on the insulating part of IPGFET cause the hysteresis characteristics. Radiant flux enhances carrier migration. [ABSTRACT FROM AUTHOR]