Analysis of Imprinted Gene Expression in Normal Fertilized and Uniparental Preimplantation Porcine Embryos

In the present study quantitative real-time PCR was used to determine the expression status of eight imprinted genes (GRB10, H19, IGF2R, XIST, IGF2, NNAT, PEG1 and PEG10) during preimplantation development, in normal fertilized and uniparental porcine embryos. The results demonstrated that, in all observed embryo samples, a non imprinted gene expression pattern up to the 16-cell stage of development was common for most genes. This was true for all classes of embryo, regardless of parental-origins and the direction of imprint. However, several differentially expressed genes (H19, IGF2, XIST and PEG10) were detected amongst the classes at the blastocyst stage of development. Most interestingly and despite the fact that maternally and paternally expressed genes should not be expressed in androgenones and parthenogenones, respectively, both uniparental embryos expressed these genes when tested for in this study. In order to account for this phenomenon, we compared the expression patterns of eight imprinted genes along with the methylation status of the IGF2/H19 DMR3 in haploid and diploid parthenogenetic embryos. Our findings revealed that IGF2, NNAT and PEG10 were silenced in haploid but not diploid parthenogenetic blastocysts and differential methylation of the IGF2/H19 DMR3 was consistently observed between haploid and diploid parthenogenetic blastocysts. These results appear to suggest that there exists a process to adjust the expression status of imprinted genes in diploid parthenogenetic embryos and that this phenomenon may be associated with altered methylation at an imprinting control region. In addition we believe that imprinted expression occurs in at least four genes, namely H19, IGF2, XIST and PEG10 in porcine blastocyst stage embryos

Induced Growth of CsPbBr3 Perovskite Films by Incorporating Metal Chalcogenide Quantum Dots in PbBr2 Films for Performance Enhancement of Inorganic Perovskite Solar Cells

Cesium lead bromide (CsPbBr3), an inorganic perovskite material with a large band gap energy (Eg = 2.3 eV), is a great candidate to produce stable and semitransparent perovskite solar cell (PSC) platforms owing to its complete and stable perovskite structure in humid environments. We synthesized quantum dots (QDs) composed of five atoms, copper (Cu), zinc (Zn), indium (In), sulfur (S), and selenium (Se; CZISSe QDs), and incorporated them into CsPbBr3 inorganic perovskite films. To enable the dispersion of CsPbBr3-capped CZISSe QDs in a PbBr2 solution, we used the ligand-exchange method to substitute an inorganic CsPbBr3 shell instead of the long organic capping chains. CZISSe QDs functioned as crystal nuclei seeds in the PbBr2 film and promoted the crystallization of CsPbBr3. Furthermore, they were present in the mesoporous TiO2-CsPbBr3 perovskite layer, improving the extraction and transport of electrons from the CsPbBr3 light absorption layer to the TiO2. Consequently, the power conversion efficiency of the QD-containing inorganic PSC was enhanced by 20.6% compared to that of the QD-free PSC. © 2020 American Chemical Society. All rights reserved.1

A miniaturized wall-climbing segment robot inspired by caterpillar locomotion

Caterpillars are very successful soft-bodied climbers that navigate in complex environments. This paper develops a multi-segmented robot climbing on vertical surfaces using dry adhesive pads, inspired by caterpillar locomotion. The miniaturized robot consists of four segments, and each segment uses a solenoid actuator with a permanent magnet plunger. The head and body segments adapt a novel mechanism and Scott-Russell linkages to generate a bi-directional plane motion using one solenoid actuator, resulting to reliable attaching and peeling motions of gecko pads. A tail is also attached at the back of the last segment to avoid falling or exhibiting unstable motion. Gecko-inspired adhesive pads are fabricated from polydimethylsiloxane (PDMS) with the area of 20 mm x 10 mm. We have conducted experiments on the locomotion performance of the segment robot climbing vertical surfaces for two types of locomotion, achieving the fast and stable climbing motion