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Ding R.,Peking University | Li T.,CAS Institute of Theoretical Physics | Li T.,University of Electronic Science and Technology of China | Staub F.,CERN | And 3 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We propose the supersymmetric Standard Models (SSMs) with a pseudo-Dirac gluino from hybrid F- and D-term supersymmetry (SUSY) breaking. Similar to the SSMs before the LHC, all the supersymmetric particles in the minimal SSM obtain the SUSY breaking soft terms from the traditional gravity mediation and have masses within about 1 TeV except gluino. To evade the LHC SUSY search constraints, the gluino also has a heavy Dirac mass above 3 TeV from D-term SUSY breaking. Interestingly, such a heavy Dirac gluino mass will not induce the electroweak fine-tuning problem. We realize such SUSY breaking via an anomalous U(1)X gauge symmetry inspired from string models. To maintain the gauge coupling unification and increase the Higgs boson mass, we introduce extra vectorlike particles. We study the viable parameter space which satisfies all the current experimental constraints and present a concrete benchmark point. This kind of model not only preserves the merits of pre-LHC SSMs such as naturalness, dark matter, etc., but also solves the possible problems in the SSMs with Dirac gauginos due to the F-term gravity mediation. © 2015 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "http://creativecommons.org/licenses/by/3.0/" Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Source

Zhu B.,Chinese Academy of SciencesBeijing | Liu C.,State Key Laboratory of Microbial Technology | Liu S.,State Key Laboratory of Microbial Technology | Cong H.,State Key Laboratory of Microbial Technology | And 3 more authors.
Environmental Microbiology | Year: 2016

Cyclic diguanosine monophosphate (c-di-GMP) is one of the most important bacterial second messengers that controls many bacterial cellular functions including lifestyle switch between plankton and biofilm. Surface attachment defective (SadC) is a diguanylate cyclase (DGC) involved in the biosynthesis of c-di-GMP in Pseudomonas aeruginosa, an opportunistic pathogen that can cause diverse infections. Here we report the crystal structure of GGDEF domain from SadC and the critical role of the trans-membrane (TM) domain of SadC with regard to biofilm formation, exopolysaccharide production and motility. We showed that over-expression of SadC in P. aeruginosa PAO1 totally inhibited swimming motility and significantly enhanced the production of exopolysaccharide Psl. SadC lacking TM domains (SadC300-487) could not localize on cytoplasmic membrane and form cluster, lost the ability to inhibit the swimming and twitching motility, and showed the attenuated activity to promote Psl production despite that SadC300-487 was able to catalyze the synthesize of c-di-GMP in vitro and in vivo. The GGDEF domain of SadC has a typical GGDEF structure and the α-helix connected the TM domains with SadC GGDEF domain is essential for SadC to form DGC oligomers. Our data imply that membrane association of SadC promotes its DGC activity by affecting the formation of active DGC oligomers. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd. Source

Wang J.,CAS Institute of Process Engineering | Zhao B.,Chinese Academy of SciencesBeijing | Li J.,CAS Institute of Process Engineering
AIChE Journal | Year: 2016

Mesoscience has recently been proposed as a possible general concept for describing complex systems far from equilibrium, however, concrete formulations are needed, and particularly, a statistical mechanics foundation of mesoscience remains to be explored. To this end, the mathematical theory of stochastic geometry is combined with the energy minimization multi-scale (EMMS) principle under the concept of mesoscience to propose a statistical mechanics framework. An EMMS-based particle velocity distribution function is then derived as an example to show how the proposed framework works, and more importantly, as a first key step toward a generalized kinetic theory for heterogeneous gas-solid flow. It was shown that the resultant EMMS-based distribution is bimodal, instead of the widely-used Maxwellian distribution, but it reduces to the Maxwellian distribution when the gas-solid system is homogeneous. The EMMS-based distribution is finally validated by comparing its prediction of the variance of solid concentration fluctuation and granular temperature with experimental data available in literature. © 2016 American Institute of Chemical Engineers. Source

Gu Y.,U.S. Geological Survey | Wylie B.K.,U.S. Geological Survey | Zhang L.,Chinese Academy of SciencesBeijing | Gilmanov T.G.,South Dakota State University
Biomass and Bioenergy | Year: 2012

This study evaluates the carbon fluxes and trends and examines the environmental sustainability (e.g., carbon budget, source or sink) of the potential biofuel feedstock sites identified in the Greater Platte River Basin (GPRB). A 9-year (2000-2008) time series of net ecosystem production (NEP), a measure of net carbon absorption or emission by ecosystems, was used to assess the historical trends and budgets of carbon flux for grasslands in the GPRB. The spatially averaged annual NEP (ANEP) for grassland areas that are possibly suitable for biofuel expansion (productive grasslands) was 71-169 g C m-2 year-1 during 2000-2008, indicating a carbon sink (more carbon is absorbed than released) in these areas. The spatially averaged ANEP for areas not suitable for biofuel feedstock development (less productive or degraded grasslands) was -47 to 69 g C m-2 year-1 during 2000-2008, showing a weak carbon source or a weak carbon sink (carbon emitted is nearly equal to carbon absorbed). The 9-year pre-harvest cumulative ANEP was 1166 g C m-2 for the suitable areas (a strong carbon sink) and 200 g C m-2 for the non-suitable areas (a weak carbon sink). Results demonstrate and confirm that our method of dynamic modeling of ecosystem performance can successfully identify areas desirable and sustainable for future biofuel feedstock development. This study provides useful information for land managers and decision makers to make optimal land use decisions regarding biofuel feedstock development and sustainability. © 2012 Elsevier Ltd. Source

Jiang F.,CAS Shanghai Institute of Applied Physics | Jiang F.,University of Chinese Academy of Sciences | Li C.,CAS Shanghai Institute of Applied Physics | Fu H.,CAS Shanghai Institute of Applied Physics | And 5 more authors.
Journal of Physical Chemistry C | Year: 2015

A temperature-dependent X-ray absorption fine structure (XAFS) study was performed to investigate structural changes in the 1-hexyl-3-methylimidazolium bromine (C6mimBr) ionic liquid (IL) confined within the channels of multiwalled carbon nanotubes (MWCNTs). The XAFS spectra at room temperature confirmed the charge transfer from the bromine anion of the encapsulated IL to the MWCNTs. R-space analysis at ambient temperature revealed the reduced distance between the anions and cations in the confined IL compared with that in the bulk state. Interfacial-induced solidification and nanoconfinement in MWCNTs induced the self-assembly of ions in the confined IL to form a layered arrangement near the inner surface of MWCNTs. In situ XAFS analysis revealed that with increasing temperature charge transferred from MWCNTs to Br anions because of the damage from the conjugative effect between Br and MWCNTs and the relatively strong electronegativity of Br atoms. R-space analysis also showed gradual reduction in distance between cations and anions with increasing temperature. This finding indicated that the anion moved toward the ring planar, and ions rearranged from the layered to the near-planar structure. Raman and XRD experiments confirmed the structural transformation of the confined IL at increased temperature. © 2015 American Chemical Society. Source

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