To further increase the mechanical properties of polyacrylonitrile-based carbon fibers, a multiple stretching technique was applied. Carbon fibers were multiple stretched at 2200 °C and characterizations such as SEM, Raman, XRD, and TEM were used to investigate the evolution of microstructure of carbon fibers. It was found that the grooves on the surface of carbon fibers along the fiber axis direction became more obvious and the cross-section of fibers were twisted from nearly circular to elliptical after multiple stretching. Growth and slippage of graphite microcrystals along the fiber axis direction resulted decrease in disordered structure and defects in the carbon fibers and increase in the degree of graphitization. The multiple stretching effectively enhanced the length-to-width ratio of microcrystals. An increase of 75 GPa in tensile modulus and a retention rate of 0.95 in tensile strength were realized for carbon fibers multiple stretched at 2200 °C.

Photocatalysis technology including hydrogen evolution from water splitting, CO2 reduction and N2 conversion to ammonia emerges as a significant approach for energy crisis and environmental pollution. For these conventional semiconductors such as TiO2, ZnO, WO3, CdS and g-C3N4, however, inefficient photoabsorption, rapid recombination of photogenerated carriers, and inadequate surface reactive sites hamper the photoinduced activity and stability. Defect engineering, especially oxygen vacancy, has recently drawn the attention of a number of investigators primarily in connection with its feasibility of regulatability, identifiability and effectiveness. A series of ferroelectric and piezoelectric semiconductors, with internal electric field generated by the polarization, are considered an excellent candidate for replacement of conventional semiconductors, because the observed charge separation ability of those is far from theoretical expectation. With the boost of oxygen vacancy, polarization behavior can be effectively regulated to further improve photocatalytic performance. Related studies based on the above background are the current hotspot of photocatalysis; this paper reviews the latest research progress of ferroelectric and piezoelectric photocatalysts with oxygen vacancy. Starting from the generation of oxygen vacancies, five preparation strategy including ion doping, thermal treatment, chemical reduction, ultraviolet irradiation, and plasma etching are introduced; advanced characterization are summarized in classification of spectroscopy, energy spectrum, electron microscopy, density function theory and in situ techniques. Secondly, the mechanism of oxygen vacancy regulated polarization and their synergistic photocatalytic reactions are reviewed and summarized. Finally, an overview on the prospect of advanced photocatalytic engineering concerned to oxygen vacancies involved ferroelectric and piezoelectric photocatalysts is proposed.

PP2A-B55α, a regulatory subunit of PP2A plays an important roles in regulating cell proliferation and survival. However, the functions for PP2A-B55α in mouse early embryo development is not clear. The objective of present were to investigate the expression patterns and to explore its biological function during mouse early development. Thetranscripts of PP2A-B55α were detected at all developmental stages in mouse embryo and decreased during embryo development. Immunostaining revealed that PP2A-B55α was present in both the nucleus and cytoplasm in early cleavage stage embryos. In the late embryonic development, PP2A-B55α was predominantly located in the cytoplasm. Knockdown (KD) of PP2A-B55α using double strand RNA not affect the proportion of cleaved embryos, but resulted in significantly decreased development to blastocyst stage and reduced total cell number in blastocyst. KD PP2A-B55α is able to induce sustained DNA damage and reduced the transcripts of non-homologous end joining (NHEJ) or homologous recombination (HR) pathways relative genes in mouse early embryo. KD PP2A-B55αcaused apoptosis and increase the transcripts of pro-apoptotic genes in blastocyst. Furthermore, The KDPP2A-B55α showed significantly lower cell proliferating rates (from 5-Bromo-deoxyuridineassayresults) in blastocysts and to talareas of out growth potential was decreased. These observation provide novel in sight into PP2A-B55α expression patterns in mouse early embryos and down-regulation of PP2A-B55α negatively impacted blastocyst development, total cell number, DNA damage, apoptosis, and proliferation and post-hatchingevents.

Web 2.0 communities are providing new opportunities for teachers’ professional development by supporting more flexible sharing, communicating, and collaborating among teachers at a distance. Meanwhile, literature concerning teachers’ professional development increasingly places value on communities of practice and web-based learning communities. This paper presents a case study on the design of teacher training supported by a Web 2.0 community. The training program discussed in the paper is characterized by employing peer-coaching to facilitate teachers’ learning in a Web 2.0 community, and is a part of a project funded by the Ford Foundation. The paper gives a brief introduction to the training program, and reports some important findings and reflections on design and practice for in-service teacher training. It includes the theoretical framework design, a training model as well as activity design, and the implementation and evaluation of the training program and useful experiences. Initially, taking account school teachers’ needs at the K12 level for curriculum reform and quality education, theory, knowledge and practice competences for learner-centered instruction were examined by using peer-coaching methods supported by online communities. The suggested training program was delivered in two Chinese districts in August 2009: Tianhe district of Guangzhou, and Wuhou district of Chengdu. More than 120 participants, including subject teachers, school principals and local teaching researchers, took part in the f2f training, online activities and the further practice activities. Even still on-going, the comprehensive investigation and evaluation of the training program explains that the initial results and observations collected during the process of training are very positive. With cause for optimism as to the prospect of achieving the training program’s goals, the study has demonstrated that a task-driven approach and peer-coaching supported by a web 2.0 community are effective methods for in-service teacher training, and that peer-coaching can be greatly extended by out-of-school activities.