In vitro fertilized (IVF) human embryos have a high incidence of developmental arrest before the blastocyst stage, therefore characterization of the molecular mechanisms that regulate embryo development is urgently required. Post-transcriptional control by microRNAs (miRNAs) is one of the most investigated RNA control mechanisms, and is hypothesized to be involved actively in developmental arrest in preimplantation embryos. In this study, we extracted total RNA from mouse 2-cell and 4-cell embryos. Using a miRNA microarray, 192 miRNAs were found to be differentially expressed in 4-cell embryos and 2-cell embryos; 122 miRNAs were upregulated and 70 were downregulated in 4-cell embryos. The microarray results were confirmed by real-time quantitative RT-PCR for six miRNAs (mmu-miR-467h, mmu-miR-466d-3p, mmu-miR-292–5p, mmu-miR-154, mmu-miR-2145, and mmu-miR-706). Cdca4 and Tcf12 were identified as miR-154 target genes by target prediction analysis. This study provides a developmental map for a large number of miRNAs in 2-cell and 4-cell embryos. The function of these miRNAs and the mechanisms by which they modulate embryonic developmental arrest require further study. The results of this study have potential applications in the field of reproductive medicine.

A series of magnetic FeCoNiAl nanocapsules was synthesized by the plasma arc discharge method; the targets of Fe, Co, Ni, and Al powders were changed with varying compositions. The compositions of the nanocapsules were found to be quite different from those of the corresponding targets; the relative amount of Al (or Ni, Co) to Fe was increased (or decreased). Structures, particles sizes, composition, surface composition, magnetic properties, and thermal stability of the nanocapsules were investigated. The saturation magnetization Ms = 106.8 emu/g and coercive force iHc = 367 Oe were achieved for the nanocapsules with the Fe62.5Co21Ni13Al2.5 target. In the FeCoNiAl nanocapsules, the binding energies of Fe, Co, and Ni were different from those of the metals Fe, Co, and Ni. The binding energies of Fe2p3/2 and Fe2p1/2 of the nanocapsules were 708.2 and 721.3 eV, respectively. The four-layer structure was proposed to give a clear statement of how the composition and phase varied radially in the nanocapsules. The major contents of the four layers—i.e., the outer shell, the inner shell, the outer core and the inner core—were amorphous alumina, crystalline alumina, transition metal oxides, and transition metal alloy, respectively. The compositions, structures, particle size, and grain size of the nanocapsules all affect their magnetic properties. In the FeCoNiAl nanocapsules, the greater th amount of the body-centered-cubic phase, the stronger the ferromagnetic magnetic properties.

A series of photochromic sol-gel films are prepared through entrapping tungsten heteropolyoxometallates (PW12O403−, SiW12O404−) and molybdenum heteropolyoxometallate (PMo12O403−) into a kind of inorganic–organic matrix cohydrolyzed from tetraethylorthosilicate and 3-aminopropyltriethoxysilane. The films show reversible photochromicity. Irradiated with ultraviolet light, the transparent films change from colorless to blue. Then, bleaching occurs when the films are in contact with air or O2 in the dark. The Keggin-type polyanions interact with R–NH3+ cations strongly, and thus disperse uniformly in the sol-gel matrix, as proved by Fourier transform infrared spectra and x-ray diffraction. The molybdenum heteropolyoxometallate sol-gel film has higher photochromic efficiency and much slower bleaching than its counterparts of tungsten heteropolyoxometallate. A charge-transfer model which is supported by electron spin resonance and related literature [T. Yamase, Chem. Rev. 98, 307, (1998)] is put forth to explain the above experimental results.