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WO3-Pd composite films were deposited on the side-face of side-polished fiber Bragg grating as sensing elements by magnetron sputtering process. XRD result indicates that the WO3-Pd composite films are mainly amorphous. Compared to standard FBG coated with same hydrogen sensitive film, side-polished FBG significantly increase the sensor's sensitivity. When hydrogen concentrations are 4% and 8% in volume percentage, maximum wavelength shifts of side-polished FBG are 25 and 55 pm respectively. The experimental results show the sensor's hydrogen response is reversible, and side-polished FBG hydrogen sensor has great potential in hydrogen's measurement.

Purpose -The purpose of this paper is to present an integrated leapfrogging mode of technological innovation for developing countries or latecomer enterprises in a certain industrial innovation field. Furthermore, this paper discusses the basic paradigm of the integrated leapfrogging innovation, analyzes the risk in the integrated leapfrogging mode, and describes the risk map of the integrated leapfrogging mode. Finally, taking the example of the integrated leapfrogging mode of technological innovation in developing China High-speed Railway, this paper carries out the simulation analysis by employing system dynamics model. Design/methodology/approach -In order to examine the impact of the integrated leapfrogging innovation risk on innovative achievements, main risk variables need to be extracted from the process of the integrated leapfrogging innovation, based on the system simulation, relationships among different variables and the impact on innovative achievements can be obtained. Findings -To prevent the risk of the integrated leapfrogging innovation across the innovation, the first thing we need to improve is the contractual relationship, which is to be fair and reasonable, according to the symmetry principles of risks and benefits, and to achieve risk-sharing and revenue sharing, in addition, all parties must be clear about their responsibilities and interests. The second is the reasonable position of the government's behavior, and it hints that the government cannot interfere too much, and its function is to provide service and support instead of ordering. The third is that enterprises should effectively prevent the risk of the integrated leapfrogging innovation through risk identification and risk early warning and risk pre-control approach. Originality/value -A new concept of integrated leapfrogging mode of technological innovation has been put forward, and the risk map of the integrated leapfrogging mode has been described. In addition, this paper proposes some suggestions to prevent the risks of the integrated leapfrogging innovation for enterprises as a reference.

Tle6 (Transducin-like enhancer of split 6) is a member of the Tle co-repressor superfamily, which is expressed in various tissues of invertebrates and vertebrates and participates in the developmental process. However, the current research has only found that the TLE6 mutation is related to infertility, and the key regulatory mechanism of TLE6 remains to be explored. In this study, we combined Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 and the Tet-on system to construct mouse spermatogonia cell lines that induced TLE6 protein knockout (KO), and studied the effect of Tle6 on mouse spermatogonia proliferation and the cell cycle. The results showed that, after drug induction, the Tle6 gene in mouse spermatogonia was successfully knocked out at the genome and protein levels, and the Tle6 gene knockout efficiency was confirmed to be 87.5% with gene-cloning technology. At the same time, we also found that the mouse spermatogonia proliferated slowly after the Tle6 knockout. Using flow cytometry, we found that the cells did not undergo significant apoptosis, and the number of cells in the S phase decreased. After real-time quantity PCR (qRT-PCR) analysis, we found that the expression of cell-proliferation-related genes, CCAAT enhancer-binding protein α(C/ebp α), granulocyte-colony stimulating factor(G-csf), cyclin-dependent kinases 4(Cdk 4), Cyclin E, proliferating cell nuclear antigen(Pcna), and S-phase kinase-associated protein 2 (Skp2) was significantly reduced, which further affected cell growth. In summary, Tle6 can regulate spermatogonia cell proliferation and the cell cycle and provide a scientific basis for studying the role of TLE6 on spermatogenesis.

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The microstructure and mechanical properties of M50 steel subjected to combining cold rolling (CR) with austempering are investigated. The microstructure is characterized using X-ray diffraction and scanning and transmission electron microscopy. The mechanical properties are measured using the uniaxial tensile and Charpy impact tests. It is observed that an excellent combination of ultimate tensile strength (2536 MPa) and impact toughness (128 J) was achieved by combining austempering with CR; of which the ultimate tensile strength increased by 10% compared with traditional martensite quenching-tempering (Q-T) specimen and the impact absorbed energy exhibited 2.3 times of that in Q-T specimen. The observation of the microstructure indicates that CR obviously refines the thickness of bainite sheaves, which is favorable for the formation of ultrafine equiaxed ferrite during tempering.

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