No. 81

April 2012

Headline News Innovation and Development

Applied Technology

Basic Science Cooperation between CAS and Local Authorities
Bioscience International Cooperation Brief News Geoscience
Applied Technology

Progress on RSFPs

Reversibly switchable fluorescent proteins (RSFPs) are molecules that switch to a new fluorescent state in response to irradiation with light of a specific wavelength. RSFPs have attracted widespread interest for emerging techniques including repeated tracking of protein behavior and super-resolution microscopy. Among the limited number of RSFPs available, only Dronpa is widely employed for most cell biology applications due to its monomeric and other favorable photochemical properties. Recently, Prof. Xu Tao and Prof. Xu Pingyong at the Institute of Biophysics, CAS discovered a unique strategy for generating RSFPs of different optical characteristics by mutating mEos2, a popular fluorescent protein that irreversibly switches from green to red when illuminated with violet light and is used well for superresolution, to eliminate the red form and make several green RSFPs. The developed RSFPs, which called mGeos, have beneficial optical characteristics such as high photon output per switch, high photostability, a broad range of switching rate, and pH-dependence, which make them potentially useful for various applications. One member of this series, mGeos-M, exhibits the highest photon budget and localization precision potential among all green RSFPs. They propose mGeos-M as a candidate to replace Dronpa for applications such as dynamic tracking, dual-color superresolution imaging, and optical lock-in detection. These genetically encoded fluorescent proteins with distinguished properties expand the current tool kit of PAFPs and allow for broad applications in dynamic live cell imaging and superresolution imaging. This work was published on line in PNAS (Feb. 28, 2012).

Research on Metal Organic Frameworks Attracts Attention

Recently, Prof. Sun Lixian was invited to write a review entitled ˇ°Mesoporous Metal Organic Frameworks: Design and Applicationsˇ± for Energy & Environmental Science. The review introduced in-depth the design, preparation and progress of the mesoporous metal organic frameworks, as well as their applications in gas storage, catalysis, sensors, adsorbents of VOCs and drug delivery. The design and synthesis of the mesoporous metal organic frameworks mainly include: (1) improving MOF pore size by means of extendable organic ligands and adjustment of generating secondary building units. (2) obtaining mesoporous MOF by combination of mixed-ligands and generating novel secondary building units. (3) using surfactants as structure directing agents. (4) making full use of specially designed spacers with hierarchical functional groups and post-synthesis acid stabilization. At present, the largest cage of mesoporous MOF is ca. 5 nm. Although the design and application of the mesoporous metal organic frameworks just started, the MOF have showed excellent performance in related fields, especially in CO2 capture, hydrogen storage and catalysis.

Lower-cost High-performance Ion Exchange Membrane Born

To develop lower cost high performance ion exchange membrane, a research team led by Prof. Xue Lixin and Asso. Prof. Tao Kang has developed a new series of high performance ion exchange membranes with high ionic conductivity and good thermal and mechanical properties. The proton conductivity of developed membranes and reach 0.227 s/cm at 80 oC which is much higher than the a tested commercial Nafion sample under the same condition, while the tensile strength and maxim extension rate of the samples reach 25.3 MPa and 45.09% respectively. The route to make these new type of ion exchange membranes is expected to be simple and at lower cost. Five patents have been filed to these new classes of ion exchange membranes.

New Tech of Biomass Power Generation to be Industrialized Soon

On March 20, 2012, a project on ˇ°Research and demonstration of key technologies of fuel synthesis and power generation from biomass gasificationˇ± undertaken by the Guangzhou Institute of Energy Conversion (GIEC), CAS passed the acceptance check. To produce high-quality syngas for DME synthesis, mixed-flow fixed bed gasifier and composite fluidized bed gasifier were developed. Special attention was paid to the integration of system units, including gasification, reforming and cleaning, syngas decarbonization, catalyzed synthesis, absorption, distillation and exhaust-gas power generation, as well as the system optimization. A demonstration project of DME synthesis and exhaust-gas power generation was developed, with an annual capacity of 1000 tons DME. The project had been operated continuously and smoothly, with a gasification efficiency over 80%, a H2/CO ratio of syngas from oxygen-rich steam gasification over 1, a one-way conversion ratio of CO over 70%, a DME selectivity over 90%, and an overall system efficiency over 38%. The application of the mixed-flow fixed bed gasifier and the composite fluidized bed gasifier developed by this project has currently been promoted, as a result of which a demonstration project of 1.5 t/h fixed bed biomass gasification replacing 2000 t/year heavy oil and a commercial project of 2ˇÁ5t/h fluidized bed biomass gasification replacing 17,000 t/year heavy oil were established.

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