No. 79

December 2011

Headline News Innovation and Development

Applied Technology

Basic Science
Bioscience International Cooperation Brief News Geoscience

Basic Science

A Review Article on the Excited-State Hydrogen Bonding Research

Recently, Zhao Guangjiu and Han Keli at the State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, were invited by Accounts of Chemical Research to contribute a review article with the title of ¡®Hydrogen Bonding in the Electronic Excited State¡¯ (Acc. Chem. Res. DOI: 10.1021/ar200135h). In this account, they reported their recent studies in the electronic excited-state hydrogen bonding dynamics and the significant role and influence of the electronic excited-state hydrogen bonding on photophysics, photochemistry, and photobiology. Combination of state-of-the-art spectroscopic experiments with quantum chemistry calculations has led to tremendous progress in the excited-state hydrogen bonding research. They demonstrated for the first time that the intermolecular hydrogen bond in the electronic excited state is greatly strengthened for coumarin chromophores and weakened for thiocarbonyl chromophores. They first clarified that intermolecular hydrogen-bond strengthening and weakening correspond to red-shifts and blue-shifts, respectively, in the electronic spectra. Moreover, various radiationless deactivations can be dramatically influenced through the regulation of electronic states by hydrogen-bonding interactions. As a consequence, the fluorescence of chromophores in hydrogen-bonded surroundings is always quenched or enhanced by hydrogen bonds. Their research expands people¡¯s understanding of the nature of hydrogen bonding by delineating the interaction between hydrogen bonds and lights, thereby providing a important basis for hydrogen bonding studies in photophysics, photochemistry, and photobiology. In addition, they presented an outlook on the future research. Since 2007, Zhao Guangjiu and Han Keli have published more than 20 articles, communications, and book chapters in the field of excited-state hydrogen bonding research. Many of them have been highly cited by other researchers. They also edited the first monograph in the field ¡®Hydrogen Bonding and Transfer in the Excited State¡¯ (Ke-Li Han and Guang-Jiu Zhao, ISBN: 978-0-470-66677-7, John Wiley & Sons Ltd, Chichester, UK, 2010). In 2011, they were invited by Physical Chemistry Chemical Physics as Guest Editors for a themed issue on hydrogen bonding in electronically excited states.

Eight-photon Entangled State Generated

Recently, researchers from the Key Lab of Quantum Information led by Prof. Guo Guangcan, Member of CAS of the University of Science and Technology of China (USTC) have successfully generated an eight-photon Greenberger-Horne-Zeilinger state and demonstrated an eight-party quantum communication complexity scenario. It refreshes the world record of generating and manipulating multi-photon entanglement. The experimental group of Li Chuanfeng and Huang Yunfeng created two-photon entanglement source by cutting the nonlinear crystal in a special way, i.e., beam-like version. The creative method improved the photon detection efficiency to 25.0% with 300-mW fem to second pulsed laser as pump. Meanwhile, the single mode optical fiber collection skill they adopted eliminated the problem of stability of light path and enhanced the entanglement of the photon pair. Then photon pairs were then connected to eight-photon entangled state by three polarization beam splitters. With help from their home-made 16-channel coincidence unit, the presence of genuine eight-partite entanglement was finally verified by the demonstration of an eight-photon Greenberger-Horne-Zeilinger state with a measured fidelity of 0.59, which they utilized further to accomplish an eight-party quantum communication complexity scenario. The achievements demonstrate that scientists have achieved an unprecedented level in generating Multi-partite entangled states with a number of eight quanta. This eight-photon entangled-state source can be applied into one-way quantum computation, quantum networks, and other quantum information processing tasks and promotes relative researches on the property and categorization of quantum entanglement. This work was published on Nature Communications of Nov. 22, 2011.

Fabrication and Application of Polymer Colloidal Photonic Crystals

Scientists from labs of New Materials and Organic Solids, Institute of Chemistry, CAS (ICCAS), have undertaken systematic research on the design, fabrication, and application of polymer colloidal photonic crystals (PCs). Review and feature articles of their research results have been recently published upon invitation by Acc. Chem. Res.£¨2011, 44, 405-415£©and J. Mater. Chem. (2011£¬21, 14113- 14126, Back Cover & hot paper). The research group in ICCAS headed by Prof. Song Yanlin has been working on PCs for many years, trying to address the key issues towards the application of the PCs, such as complicated and time consuming fabrication methods, poorly controllable wettability and limited mechanical properties. The group has developed a series of functional polymer colloidal photonic crystals via the design of the building block ¨C the latex particles. Through tuning the surface chemical composition and physical morphologies of individual latex particles, colloidal PCs with controllable wettability and high mechanical properties can be achieved. Moreover, facile fabrication methods for the polymer colloidal PCs such as spray-coating and ink-jet printing have also been developed, and promising applications in high efficient lighting, sensing, bio-dectection and data storage have been demonstrated. The reported progress is of significance for the development and application of polymer colloidal PCs.

Progress in Analysis on Alzheimer¡¯s Disease Pathogenesis

Recently, a research team led by Prof. Lei Hongxing at the Beijing Institute of Genomics (BIG), CAS, reported the progress made on the comprehensive analysis of the mechanism of Alzheimer¡¯s disease (AD). The article titled ¡°Down-Regulation of Energy Metabolism in Alzheimer's Disease is a Protective Response of Neurons to the Microenvironment¡± was published online by Journal Alzheimer's Disease in October, 2011. In this work, based on the combination of the high quality microarray datasets encompassing different stages of AD, the researchers propose that the down-regulation of energy metabolism in AD is a protective response of the neurons to the reduced level of nutrient and oxygen supply in the microenvironment, and the elevated apoptosis at the late stage of AD is triggered by the conflict between the low level of energy metabolism and high level of regulatory and repair burden. This new hypothesis has significant implication for pharmaceutical intervention of Alzheimer¡¯s disease.

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