Transportation of single cell and microbubbles by phase-shift introduced to standing leaky surface acoustic waves

A microfluidic device was developed to precisely transport a single cell or multiple microbubbles by introducing phase-shifts to a standing leaky surface acoustic wave (SLSAW). The device consists of a polydimethyl-siloxane (PDMS) microchannel and two phase-tunable interdigital transducers (IDTs) for the generation of the relative phase for the pair of surface acoustic waves (SAW) propagating along the opposite directions forming a standing wave. When the SAW contacts the fluid medium inside the microchannel, some of SAW energy is coupled to the fluid and the SAW becomes the leaky surface wave. By modulating the relative phase between two IDTs, the positions of pressure nodes of the SLSAW in the microchannel change linearly resulting in the transportation of a single cell or microbubbles. The results also reveal that there is a good linear relationship between the relative phase and the displacement of a single cell or microbubbles. Furthermore, the single cell and the microbubbles can be transported over a predetermined distance continuously until they reach the targeted locations. This technique has its distinct advantages, such as precise position-manipulation, simple to implement, miniature size, and noninvasive character, which may provide an effective method for the position-manipulation of a single cell and microbubbles in many biological and biomedical applications.     

Preimplantation genetic diagnosis for Down syndrome pregnancy

Objective： To evaluate the effect ofpreimplantation genetic diagnosis （PGD） conducted for women who had Down syndrome pregnancy previously. Methods： Trisomy 21 was diagnosed by using fluorescence in site hybridization （FISH） before embryo transfer in two women who had Down syndrome pregnancies. Each received one or two PGD cycles respectively. Results： Case 1： one PGD cycle was conducted, two oocytes were fertilized and biopsied. One embryo is of trisomy 21 and the other of monosomy 21. No embryo was transferred. Case 2： two PGD cycles were conducted, in total, sixteen oocytes were fertilized and biopsied. Four embryos were tested to be normal, six of trisomy 21, and one of monosomy 21. Five had no signal. Four normal embryos were transferred but no pregnancy resulted. Conclusion： For couples who had pregnancies with Down syndrome previously, PGD can be considered, and has been shown to be an effective strategy.     

Normal epigenetic inheritance in mice conceived by in vitro fertilization and embryo transfer

An association between assisted reproductive technology (ART) and neurobehavioral imprinting disorders has been reported in many studies, and it seems that ART may interfere with imprint reprogramming. However, it has never been explored whether epigenetic errors or imprinting disease susceptibility induced by ART can be inherited transgenerationally. Hence, the aim of this study was to determine the effect of in vitro fertilization and embryo transfer (IVF-ET) on transgenerational inheritance in an inbred mouse model. Mice derived from IVF-ET were outcrossed to wild-type C57BL/6J to obtain their female and male line F2 and F3 generations. Their behavior, morphology, histology, and DNA methylation status at several important differentially methylated regions (DMRs) were analyzed by Morris water maze, hematoxylin and eosin (H&E) staining, and bisulfite genomic sequencing. No significant differences in spatial learning or phenotypic abnormality were found in adults derived from IVF (F1) and female and male line F2 and F3 generations. A borderline trend of hypomethylation was found in H19 DMR CpG island 3 in the female line-derived F3 generation (0.40±0.118, P=0.086). Methylation status in H19/Igf2 DMR island 1, Igf2 DMR, KvDMR, and Snrpn DMR displayed normal patterns. Methylation percentage did not differ significantly from that of adults conceived naturally, and the expression of the genes they regulated was not disturbed. Transgenerational integrity, such as behavior, morphology, histology, and DNA methylation status, was maintained in these generations, which indicates that exposure of female germ cells to hormonal stimulation and gamete manipulation might not affect the individuals and their descendents.     

吴中伦的《云南植物考察日记》

１９３４年,吴中伦（１９１３－１９９５）等人赴云南进行自然资源调查,他将所经地区的自然环境,植物种类,森林资源以及风土人情等逐日记记录下来,形成一部十几万言的《云南植物考察日记》。该文介绍了这部日启的产生过程及主要内容,并认为其有着重要的学术价值。     

Cobalt-Free BaFe0.6Zr0.1Y0.3O3-δ Oxygen Electrode for Reversible Protonic Ceramic Electrochemical Cells

Reversible protonic ceramic electrochemical cells(R-PCECs) are ideal, high-efficiency devices that are environmentally friendly and have a modular design. This paper studies BaFe_0.6Zr_0.1Y_0.3O_3-δ(BFZY3) as a cobalt-free perovskite oxygen electrode for high-performance R-PCECs where Y ions doping can increase the concentration of oxygen vacancies with a remarkable increase in catalytic performance. The cell with configuration of Ni-BZCYYb/BZCYYb/BFZY3 de...     

Carbon-emission calculation of electromechanical energy consumption of different structures during the construction phase

Due to the use of mechanical and electrical equipments in different buildings during construction phase, energy consumption produces large amounts of carbon emissions.Based on the energy use of China, we established a formula that was applicable to carbon-emission calculation, and discussed carbon-emission characteristics of concrete structures and steel construction.Owing to the difference of electrical and mechanical equipment used in construction phase, the results show that under the same conditions, the carbon emission intensity of a concrete structure building is much higher than that of a steel building.At last, we also put forward some emission reduction measures based on the calculation data of different buildings.     

高校“数据结构”课程教改现状与经验

分析和总结了国内外高等学校“数据结构”教改的研究和实践进展。提出“先修课程”“培养目标与课程知识点的接合问题”和“计算机辅助教学工具的使用”是数据结构课程面临的三个亟待解决的重要问题,并在此基础上,介绍了美国University of New Hampshire大学及成都大学数据结构教改经验,希望能为数据结构这门课程的教学提供有益的参考。     

Deep carbon cycling during subduction revealed by coexisting diamond-methane-magnesite in peridotite

<正>Subduction is an important process for transferring materials from the surface into the deep mantle.During subduction,recycled carbon can be released from the subducting slab to the mantle wedge through various decarbonation processes.Both oxidized(CO₂/CO₃^2-) and reduced(CH₄) carbon-bearing species have been discovered in(ultra)high-pressure(HP-UHP) subduction zones worldwide [1-3].Diamond is a typical index mineral for UHP metamorphism.     

Surface modification of ZnIn2S4 layers to realize energy-transfer-mediated photocatalysisOA

Photocatalytic selective aerobic oxidation reactions are crucial in designing advanced organic intermediates,but suffer from low conversion efficiency.Hence,activating ¹O₂ to create suitable reactive oxygen species,such as singlet oxygen(¹O₂),can significantly increase the yield of desired products.Herein,using ZnIn₂S₄ nanosheets as a model system,we build a surface-modified theoretical structure,where a surface-covered non-conduc...     

Tuning 2D magnetism in Fe3+XGeTe2 films by element dopingOA

Two-dimensional(2D) ferromagnetic materials have been discovered with tunable magnetism and orbital-driven nodal-line features. Controlling the 2D magnetism in exfoliated nanoflakes via electric/magnetic fields enables a boosted Curie temperature(T_C) or phase transitions. One of the challenges, however, is the realization of high T_C2D magnets that are tunable, robust and suitable for large scale fabrication. Here, we report molecular-beam epitaxy growth of wafer-scale Fe