A Laplace pressure based microfluidic trap for passive droplet trapping and controlled release

Here, we present a microfluidic droplet trap that takes advantage of the net Laplace pressure force generated when a droplet is differentially constricted. Mathematical simulations were first used to understand the working range of the component; followed by finite element modeling using the CFD software package to further characterize the behavior of the system. Controlled release of the trapped droplets is also demonstrated through both a mechanical method and a chemical method that manipulates the total pressure exerted on the trapped droplet. The unique design of this trapping device also provides the capability for selection of a single droplet from a train, as well as droplet fusion.     

我国大陆与香港地区高等教育合作办学的历史发展与趋势展望

香港与大陆两地的教育合作办学经历了萌芽阶段、探索阶段和稳定发展阶段,在引进香港优质专业、课程、教师等教育资源方面发挥了相当的作用,取得了一定的进展,但也存在地域发展不平衡、学科专业设置存在局限,自主招生、单文凭发放增加了教学质量保障的难度,合作办学积极性有待提高等问题.鉴于两地无论政治、经济还是文化关系的密切,高等教育作为经济发展的坚强后盾,必然成为两地合作发展的突破口.今后两地应在高等教育合作办学方面进一步完善政策法规,创造宽松、良好的办学环境;利用地缘优势,加强深港合作,促进粤港澳高等教育一体化;加强国家宏现调控,健全质量保障机制,保证合作办学质量.     

开展课外科研活动培养化学创新人才

课外科研活动是实现课堂教学与社会实践相结合的重要环节,是推动教学改革、提高学生综合素质、培养学生实践动手能力和创新精神的有效途径.对化学专业而言.开展课外科研活动要根据学科的特点,首先应选择好科研活动课题,然后,要切实做好实验方案的设计、实验方案的实施、课题的总结等三个阶段的工作,探讨开展化学课外科研活动的途径,培养化学创新人才.     

高等学校预算外有偿服务会计科目设置和核算方法探讨

本文根据会计科目设置和会计核算方法原理，结合具体实践，对高校预算外有偿服务会计核算方法，帐务处理和科目运用作了初步探讨。     

Reagentless biosensor based on layer-by-layer assembly of functional multiwall carbon nanotubes and enzyme-mediator biocomposite

A simple and controllable layer-by-layer (LBL) assembly method was proposed for the construction of reagentless biosensors based on electrostatic interaction between functional multiwall carbon nanotubes (MWNTs) and enzyme-mediator biocomposites. The carboxylated MWNTs were wrapped with polycations poly(allylamine hydrochloride) (PAH) and the resulting PAH-MWNTs were well dispersed and positively charged. As a water-soluble dye methylene blue (MB) could mix well with horseradish peroxidase (HRP) to form a biocompatible and negativelycharged HRP-MB biocomposite. A (PAH-MWNTs/HRP-MB) _n bionanomultilayer was then prepared by electrostatic LBL assembly of PAH-MWNTs and HRP-MB on a polyelectrolyte precursor film-modified Au electrode. Due to the excellent biocompatibility of HRP-MB biocomposite and the uniform LBL assembly, the immobilized HRP could retain its natural bioactivity and MB could efficiently shuttle electrons between HRP and the electrode. The incorporation of MWNTs in the bionanomultilayer enhanced the surface coverage concentration of the electroactive enzyme and increased the catalytic current response of the electrode. The proposed biosensor displayed a fast response (2 s) to hydrogen peroxide with a low detection limit of 2.0×10⁻⁷ mol/L (S/N=3). This work provided a versatile platform in the further development of reagentless biosensors.     

Microcalorimetry studies on the antibacterial effect of crude monkshood polysaccharide

In this paper, crude monkshood polysaccharide was isolated from Radix Aconiti Lateralis Preparata. The effects of crude monkshood polysaccharide on Escherichia coli and Staphylococcus aureus were investigated by microcalorimetry. The power-time curves of the bacterial growth at various concentrations (c) of crude monkshood polysaccharide were plotted with a TAM air isothermal microcalorimeter at 37 °C. The growth rate constant (μ), inhibitory ratio (I), peak-height (P _m), and peak-time (t _m) were calculated. From the data, the relationship between μ and c also was established. The growth rate constant μ decreased with the increasing concentrations of crude monkshood polysaccharide. Moreover, P _m reduced and t _m increased with increasing concentrations. The experimental results revealed that crude monkshood polysaccharide had inhibitory activity towards S. aureus and E. coli. Results obtained from our study strongly suggest that microcalorimetry is a fast, simple, and more sensitive technology that can be easily performed to study the effect of drugs on bacteria.     

“亚道德”不能逾越“道德底线”——“受贿扶贫”的法理评思

"亚道德"的法律评价只能是不道德;法律特别是刑法是对公民的最低的道德要求,"亚道德"不能逾越作为道德底线的法律、特别是刑法上的道德义务;即便是动机高尚的"亚道德"行为,只要符合犯罪的构成要件理应成立犯罪.     

Optimization of construction machinery scheme of cast-in-situ concrete based on the improved scatter degree method

The basic requirement of mechanical construction of cast-in-situ concrete is that it could not only conduct quality qualification and safety production, but also achieve most economic benefits with less investment under the condition to meet the needs of project duration. Therefore, the selection of construction machinery scheme plays an important role. However, in the actual construction, it is usually that operators rely on their own experience and field conditions to determine the mechanics. Such a method is subjective and arbitrary, and it is not conducive to make the construction rationally. Considering the above reasons, an improved weight coefficient method was used to establish an estimation model to estimate the construction machinery scheme of cast-in-situ concrete, so as to make the procedure much rational.     

Fluorescent co-localization of PTS1 and PTS2 and its application in analysis of the gene function and the peroxisomal dynamic in Magnaporthe oryzae

The peroxisomal matrix proteins involved in many important biological metabolism pathways in eukaryotic cells are encoded by nucleal genes, synthesized in the cytoplasm and then transported into the organelles. Targeting and import of these proteins depend on their two peroxisomal targeting signals (PTS1 and PTS2) in sequence as we have known so far. The vectors of the fluorescent fusions with PTS, i.e., green fluorescence protein (GFP)-PTSI, GFP-PTS2 and red fluorescence protein (RFP)-PTS1, were constructed and introduced into Magnaporthe oryzae Guy11 cells. Transformants containing these fusions emitted fluorescence in a punctate pattern, and the locations of the red and green fluorescence overlapped exactly in RFP-PTS1 and GFP-PTS2 co-transformed strains. These data indicated that both PTS 1 and PTS2 fusions were imported into peroxisomes. A probable higher efficiency of PTSI machinery was revealed by comparing the fluorescence backgrounds in GFP-PTS1 and GFP-PTS2 transformants. By introducing both RFP-PTS1 and GFP-PTS2 into △mgpex6 mutants, the involvement of MGPEX6 gene in both PTS1 and PTS2 pathways was proved. In addition, using these transformants, the inducement of peroxisomes and the dynamic of peroxisomal number during the pre-penetration processes were investigated as well. In summary, by the localization and co-localization of PTSI and PTS2, we provided a useful tool to evaluate the biological roles of the peroxisomes and the related genes.