Time filter

Source Type

Sichuan, China

Shen C.-X.,CAS Institute of Computing Technology | Chen X.-S.,Sichuan University
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2014

According to the revelation of American cyberspace security strategy, the main task and challenges of information security in China were described. In terms of strengthening the construction of information security system, trusted computing system framework, the innovation and development of trusted computing and so on, how to use trusted computing for actively build a deep defense system and the innovation of the construction process of this system were elaborated. Finally, some suggestions in defence of sovereignty for cyberspace, independent research and development, network security frame, personnel training and development treads were put forward.

Mao H.,University of Sichuan | Chen C.,University of Sichuan | Liao X.,University of Sichuan | Shi B.,University of Sichuan | Shi B.,Sichuan University
Journal of Molecular Catalysis A: Chemical | Year: 2011

Black wattle tannin (BT), a typical natural plant polyphenol, was grafted onto collagen fiber (CF) to act as the stabilizer and carrier of Pd nanoparticles, and as a result, a recyclable heterogeneous Pd catalyst (Pd-BT-CF) was synthesized. The main physicochemical properties of the Pd-BT-CF catalyst were characterized by Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Transmission Electron Microscopy (TEM). It was found that the catalyst was in an ordered fibrous state, on which Pd nanoparticles with diameter of 4 nm were highly dispersed. Subsequently, the Pd-BT-CF catalyst was employed for the hydrogenation of quinoline. The influences of reaction time, temperature, H2 pressure and solvent on the catalytic hydrogenation of quinoline were systematically investigated. The experimental results suggested that the Pd-BT-CF catalyst exhibited high catalytic activity and selectivity for quinoline hydrogenation. The average turnover frequency (TOF) of Pd-BT-CF was as high as 165.3 mol mol-1 h-1, and the selectivity to 1,2,3,4-tetrahydroquinoline was 100% when the reaction was carried out at 60 °C and 2.0 MPa for 1.0 h. Moreover, the activity and selectivity of Pd-BT-CF catalyst were not significantly reduced after being reused 6 times, exhibiting a satisfied reusability. Further XPS, Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and TEM analyses confirmed that the Pd species were stabilized by the hydroxyls of BT-CF, which prevented the aggregation and leakage of Pd during the reaction. © 2011 Elsevier B.V. All rights reserved.

Zheng H.,National Institute of Nuclear Physics, Italy | Zheng H.,Texas A&M University | Zhu L.,Sichuan University | Bonasera A.,National Institute of Nuclear Physics, Italy | Bonasera A.,Texas A&M University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Using the experimental data from the STAR, PHENIX, ALICE, and CMS programs on the rapidity and energy dependence of the pT spectra in p+p collisions, we show that a universal distribution exists. The energy dependence of temperature T and parameter n of the Tsallis distribution are also discussed in detail. A cascade particle production mechanism in p+p collisions is proposed. © 2015 American Physical Society. © 2015 American Physical Society.

Liu W.,Beihang University | Liu W.,Sichuan University | Sun K.,University of Michigan | Wang R.,Beihang University
Nanoscale | Year: 2013

The structure evolution behaviors of NiAu nanospindles in oxidizing/vacuum conditions were studied by in situ scanning transmission electron microscopy. The spindle structure transforms into Ni@Au@NiO multi-shell structure in the oxidizing atmosphere following an oxidation-driving multilayer reconstruction mechanism. In the vacuum condition, the NiAu nanospindles evolve along four distinct stages: (i) polyhedron recrystallization of Ni matrix; (ii) facets-selected segregation and recrystallization of Au component; (iii) single crystallization of Ni matrix; (iv) wrapping diffusion of Au component. The investigation here provides a practical insight into the structural stability of NiAu bimetallic catalysts through a thermal processes. © 2013 The Royal Society of Chemistry.

Soh W.T.,National University of Singapore | Zhong X.,National University of Singapore | Zhong X.,Sichuan University | Ong C.K.,National University of Singapore
Applied Physics Letters | Year: 2014

FeAlSi (Sendust) is known to possess excellent soft magnetic properties comparable to traditional soft magnetic alloys such as NiFe (Permalloy), while having a relatively higher resistance for lower eddy current losses. However, their dynamic magnetic and magneto-transport properties are not well-studied. Via the spin rectification effect, we electrically characterize a series of obliquely sputtered FeAlSi films at ferromagnetic resonance. The variations of the anisotropy fields and damping with oblique angle are extracted and discussed. In particular, two-magnon scattering is found to dominate the damping behavior at high oblique angles. An analysis of the results shows large anomalous Hall effect and anisotropic magneto-resistance across all samples, which decreases sharply with increasing oblique incidence. © 2014 AIP Publishing LLC.

Zhang H.,Sichuan University | Miyamoto Y.,Technology Research Association for Single Wall Carbon Nanotubes TASC | Miyamoto Y.,Japan National Institute of Advanced Industrial Science and Technology
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

By performing the first-principles simulation of electron-ion dynamics based on the time-dependent density-functional theory, we propose a way to produce graphene from graphene oxides by means of the laser-induced reduction without using chemical species. Epoxy and hydroxyl groups on graphene sheets can be completely removed upon irradiation with femtosecond laser without damaging the graphene sheet. By comparing the simulated results with different pulse shapes and intensities, optimum conditions of the femtosecond laser for reduction of graphene oxide were determined. The current works will be useful for further experimental researches. © 2012 American Physical Society.

Yang Z.,Zhejiang University | Yu Y.,Zhejiang University | Zhang V.,University of California at Berkeley | Tian Y.,Zhejiang University | And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Starved animals often exhibit elevated locomotion, which has been speculated to partly resemble foraging behavior and facilitate food acquisition and energy intake. Despite its importance, the neural mechanism underlying this behavior remains unknown in any species. In this study we confirmed and extended previous findings that starvation induced locomotor activity in adult fruit flies Drosophila melanogaster. We also showed that starvation-induced hyperactivity was directed toward the localization and acquisition of food sources, because it could be suppressed upon the detection of food cues via both central nutrient-sensing and peripheral sweet-sensing mechanisms, via induction of food ingestion. We further found that octopamine, the insect counterpart of vertebrate norepinephrine, as well as the neurons expressing octopamine, were both necessary and sufficient for starvation-induced hyperactivity. Octopamine was not required for starvation-induced changes in feeding behaviors, suggesting independent regulations of energy intake behaviors upon starvation. Taken together, our results establish a quantitative behavioral paradigm to investigate the regulation of energy homeostasis by the CNS and identify a conserved neural substrate that links organismal metabolic state to a specific behavioral output. © 2015, National Academy of Sciences. All rights reserved.

Ding J.,King Abdullah University of Science and Technology | Lin Z.,Nanyang Technological University | Wu J.,Sichuan University | Dong Z.,Nanyang Technological University | Wu T.,King Abdullah University of Science and Technology
Small | Year: 2015

Materials with mesoscopic structural and electronic phase separation, either inherent from synthesis or created via external means, are known to exhibit functionalities absent in the homogeneous counterparts. One of the most notable examples is the colossal magnetoresistance discovered in mixed-valence manganites, where the coexistence of nano-to micrometer-sized phase-separated domains dictates the magnetotransport. However, it remains challenging to pattern and process such materials into predesigned structures and devices. In this work, a direct laser interference irradiation (LII) method is employed to produce periodic stripes in thin films of a prototypical phase-separated manganite Pr0.65(Ca0.75Sr0.25)0.35MnO3 (PCSMO). LII induces selective structural amorphization within the crystalline PCSMO matrix, forming arrays with dimensions commensurate with the laser wavelength. Furthermore, because the length scale of LII modification is compatible to that of phase separation in PCSMO, three orders of magnitude of increase in magnetoresistance and significant in-plane transport anisotropy are observed in treated PCSMO thin films. Our results show that LII is a rapid, cost-effective and contamination-free technique to tailor and improve the physical properties of manganite thin films, and it is promising to be generalized to other functional materials. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hu X.,Sichuan University
Guangxue Xuebao/Acta Optica Sinica | Year: 2010

Light feedback of external cavity and movement of external cavity mirror in self-mixing interference affect laser frequency. Light fields out of front and rear facets on internal cavity, frequency shift of laser and frequency of self-mixing interference signal are introduced from a model of complex resonant cavity. Frequency shift of laser and frequency spectra of self-mixing interference signal are observed in experiment. Frequency shift of laser is made up resonance frequency shift and movement frequency shift. At lower moving frequency of external cavity mirror, frequency shift of laser out of the front and rear facets are almost the same as resonance frequency shift. At higher moving frequency of external cavity mirror, frequency shift of laser out of the front and rear facets are different from each other. Frequency shift of laser out of the front facet may be dominated by movement frequency shift. Frequency of self-mixing interference signals at extremely weak feedback light is the same as Doppler frequency shift of feedback light. Frequency of self-mixing interference signal at weak feedback light vibrates sharply and its highest frequency is more than 1.6 times of Doppler frequency shift of feedback light.

Wu X.-X.,Civil Aviation Flight University of China | Zheng W.-C.,Sichuan University
Applied Magnetic Resonance | Year: 2014

The spin-Hamiltonian parameters (g factors g//, g⊥ and zero-field splitting D) of the isoelectronic 3d3 ions Cr3+, Mn4+ and Fe5+ in rhombohedral phase of BaTiO3 are calculated from the high-order perturbation formulas based on the two-mechanism model, where the contributions to spin-Hamiltonian parameters due to both the crystal-field (CF) mechanism concerning the interaction of CF excited states with ground state and the charge-transfer (CT) mechanism concerning that of CT excited states with ground state are contained. The calculated results are in reasonable agreement with the experimental values. The calculations indicate that the relative importance of CT mechanism increases with the increasing valence state of 3d3 ions and that the fact of gi(i=//,⊥)>ge(≈2.0023, the free-electron g value) for Fe5+ in BaTiO3 is due to the contributions of CT mechanism being larger than those of CF mechanism. So, for the high valence state dn ions in crystals, the rational explanations of spin-Hamiltonian parameters should take both CF and CT mechanisms into account. The local trigonal distortions (characterized by the off-center displacements Δz of 3d3 ions) of 3d3 impurity centers in BaTiO3 crystals are also estimated. These trigonal distortions differ not only from that in the host BaTiO3 crystal, but also from impurity to impurity. © 2014, Springer-Verlag Wien.

Wu X.-X.,Civil Aviation Flight University of China | Yu X.-P.,Civil Aviation Flight University of China | Zheng W.-C.,Sichuan University
Applied Magnetic Resonance | Year: 2014

The spin-Hamiltonian parameters (zero-field splitting D, g-factors g //, g ⊥ and hyperfine structure constants A //, A ⊥) of Cr3+ and Mn4+ ions at the trigonal Ga3+ site of Ca3Ga2Ge3O12 (CGGG) garnet crystals are calculated from the high-order perturbation formulas based on the two-mechanism model. In the model, besides the contributions to spin-Hamiltonian parameters from the crystal-field (CF) mechanism in the frequently applied CF theory, those from the charge-transfer (CT) mechanism (which is neglected in CF theory) are taken into account. The calculated results are in reasonable agreement with the experimental values. The defect structures of Cr3+ and Mn4+ impurity centers in CGGG crystals are also obtained from the calculations. The calculations show that the relative importance of CF mechanism (characterized by {pipe}QCT/QCT{pipe}, where Q = D,Δ (Formula Presented)) for Mn4+ center in CGGG is larger than that for Cr3+ center. So, for the high valence state dn ions in crystals, the reasonable calculations of spin-Hamiltonian parameters should consider the contributions due to both the CF and CT mechanisms. © 2014 Springer-Verlag Wien.

Li W.,Tibet Agricultural and Animal Husbandry College | Li W.,Sichuan University
Journal of Alloys and Compounds | Year: 2012

The structural phase transition and elastic properties of IrN are studied by using the pseudopotential plane wave methods within the Perdew-Burke- Ernzerhof (PBE) form of generalized gradient approximation (GGA). Six candidate structures are chosen to investigate for IrN, namely, rocksalt (B1), cesium chloride (B2), zinc blende (B3), wurtzite (B4), NiAs (B8) and tungsten carbide (Bh) type. On the basis of enthalpy versus pressure is data obtained from the theoretical calculations for high-pressure, the results show that the phase sequence of IrN is B3 → B4 → B8 → B2. The obtained phase transitions are respectively at ca. 1.98, 97.90 and 296.64 GPa. Especially, the elastic properties of B4 IrN under high pressure are studied for the first time. It is found that the elastic constants, the bulk moduli, shear moduli, compressional and shear wave velocities as well as Debye temperature of B4 IrN increase monotonically with increasing pressure. By analyzing G/B, the brittle-ductile behavior of IrN is assessed. This is a quantitative investigation on the structural and thermodynamic properties of IrN, and it still awaits experimental confirmation. © 2012 Elsevier B.V. All rights reserved.

Zhang H.,Sichuan University | Miyamoto Y.,Japan National Institute of Advanced Industrial Science and Technology | Rubio A.,University of the Basque Country
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We have used first-principles simulations based on time-dependent density functional theory to show that short laser pulses can trigger preferential hydrogen desorption from the upper or lower side of suspended graphane (H-terminated graphene). This control is achieved by using intense ultrashort p-polarized laser pulses (∼2 fs) with an asymmetric time envelope. The dynamical Stark effect induced by the pulse creates an asymmetric charge distribution and force field on the H ions, even at low laser fluence. At finite temperatures the carbon-hydrogen stretching softens, favoring H desorption from one side. This transient geometry can be modified by halogen functionalization, which results in a two-dimensional dipolar structure. © 2012 American Physical Society.

Lin Y.,Sichuan University | Li S.,CAS Institute of Zoology
ZooKeys | Year: 2013

Two new spider species of the family Mysmenidae Petrunkevitch, 1928 are reported from Southwestern China, i.e., Mysmena wawuensis sp. n. (male and female) from Sichuan and Trogloneta yuensis sp. n. (male) from Chongqing. Diagnoses and illustrations of the new species are provided. © Yucheng Lin, Shuqiang Li.

Rui L.,Sichuan University | Rui L.,Chengdu University of Information Technology
Journal of Convergence Information Technology | Year: 2012

It is well-known that the correct evaluation for computer network attack is very significant to avoid computer network attack.In order to improve the generalization performance of relevance vector machine,an incremental relevance vector machine algorithm is firstly presented and applied to computer network attack evaluation in the paper. In the study,we collect 230 samples of KDDCUP99 datasets to study the evaluation performance of incremental relevance vector machine algorithm for computer network attack.Finally,the comparison of the evaluation results among IRVM,RVM,SVM is given.It is indicated that the evaluation results of the incremental relevance vector machine model for computer network attack is better than those of RVM,SVM.

Lu H.,Queen Mary, University of London | Gillin W.P.,Queen Mary, University of London | Gillin W.P.,Sichuan University | Hernandez I.,University of Cantabria
Physical Chemistry Chemical Physics | Year: 2014

In this paper, a series of Er3+-doped Y2O3 samples are systematically investigated, focusing on the effect of the doping concentration on the emission lifetime and spectrum under both 488 nm and 980 nm excitations. Decay times of the 4S3/2 and 4F9/2 emitting states under 488 nm and 980 nm excitations are found to be different and concentration dependent. We explain these variations in terms of the changes in the up-conversion routes caused by the predominance of energy exchanges that involve the lowest lying excited states. © the Partner Organisations 2014.

Jin J.,Sichuan University
Optics and Lasers in Engineering | Year: 2012

This paper presents a new image encryption/decryption scheme. The behavior of a number of elementary cellular automata (ECA) of length 8 with periodic boundary conditions is investigated. It is found in the state-transition diagram that some ECA rules result in state attractors which satisfies basic requirement of the encryption scheme that can perform encrypting function to transform the pixel values. The generation of these attractors depending only on the rule and initial state of the CA, without any additional hardware cost for the implementation, and requires minimized computational resources. Simulation results on some grayscale and color images show that the proposed image encryption method satisfies the properties of confusion and diffusion, execution speed and has perfect information concealing. © 2012 Elsevier Ltd.

Yang K.,Sichuan University
Applied Mechanics and Materials | Year: 2014

Deceleration has a great influence on the whole traffic flow in real traffic. Based on the SDNS cellular automaton (CA) traffic model, an improved single lane traffic model with considering the safe deceleration was proposed. The model not only simulated the interaction between vehicles, but also reproduced nonlinear phenomena which tallies with real traffic such as the synchronism flow and the metastable state. The model in this paper can reduce some vehicles to decelerate. Simulation is shown that the smaller the p is, the more remarkable the variation of the proportion of the vehicle is in the early stage. © (2014) Trans Tech Publications, Switzerland.

Hu X.,Sichuan University
Guangxue Xuebao/Acta Optica Sinica | Year: 2010

The amplitude and waveform of self-mixing interference signal change periodically with static length of external cavity. The changes of the amplitude and waveform are measured experimentally with variation of static length of external cavity. And, the variation of the amplitude with static length of external cavity is calculated by superposing of self-mixing interference signal of multi-longitudinal mode laser. Then, that variation of the waveform is analyzed by considering the effect of feedback light on reflectivity of laser-cavity and laser medium gain coefficient. Results show that, the variation period of self-mixing interference signal of multi-longitudinal mode laser with static length of external cavity is equal to optical length of laser cavity. While, the width of main maximum region of self-mixing interference signal with variation of static length of external cavity is equal to the coherence length of laser which is less than the optical length of laser cavity. The periodical variation of the amplitude with static length of external cavity comes from self-mixing interference of multi-longitudinal mode laser, and that of the waveform is caused by nonlinear effect produced from feedback light acted on laser cavity and laser medium.

Kang R.,Civil Aviation Flight University of China | Yang K.,Sichuan University
Wuli Xuebao/Acta Physica Sinica | Year: 2013

Based on the NaSh model, the rules of straight movement and lane change are defined while considering the change of driving behavior under the guidance of traffic signs at ramp; besides, a traffic model with sensitive lane change under the cellular automation is proposed. Furthermore, computer numerical simulation result indicates that the procedure of sensitive lane change can effectively reduce the lane change ratio of the straight moving vehicles, thus obviously it has an inhibitory effect on unnecessary lane change; what is more, the longer the sensitive lane change zone, the more effective the inhibitory function is. However, the traffic signs at ramp cannot be set as far as possible. Lower the lane change ratio is, shorter the sensitive lane change zone needed is. The traffic signs at ramp are set with proper distance according to the lane change ratio can effectively increase systematic traffic flow as well as the critical entrance probability. © 2013 Chinese Physical Society.

Xin Z.,Sichuan University | Dobson K.,Virginia Polytechnic Institute and State University | Shinoda Y.,Nihon University | Poon T.-C.,Nihon University
Optics Letters | Year: 2010

A method is presented for the reconstruction of sectional images without the out-of-focus haze from a hologram generated by optical scanning holography. A random-phase pupil is adopted in the process of recovering individual sections from the hologram. The main idea of this approach is to recover a prescribed section while dispersing the energy from other sections into "specklelike patterns," which can be eliminated subsequently by averaging of multiple section images. © 2010 Optical Society of America.

Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The s-wave pion-pion (ππ) scattering lengths are computed below the inelastic threshold by the Lüscher technique with pion masses ranging from 240 to 463 MeV. In the Asqtad-improved staggered fermion formulation, we calculate the ππ four-point functions for the I=0 and 2 channels with "moving" wall sources without gauge fixing, and we analyze them at the next-to-leading order in the continuum three-flavor chiral perturbation theory. At the physical pion mass, we secure the s-wave ππ scattering lengths as mπaππI=0=0.214(4)(7) and mπaππI=2=-0. 04430(25)(40) for the I=0 and 2 channels, respectively, where the first uncertainties are statistical and the second ones are our estimates of several systematic effects. Our lattice results for the s-wave ππ scattering lengths are in good accordance with available experimental reports and theoretical forecasts at low momentum. A basic ingredient in our study for the I=0 case is properly incorporating the disconnected diagram. These lattice computations are carried out with the MILC 2+1 flavor gauge configurations at two lattice spacings, a≈0.15 and 0.12 fm. © 2013 American Physical Society.

Wang Z.S.,Sichuan University
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2010

Cloning and expression of gsiB was carried out for studying protein structure and function of glutathione transport system. The coding sequence of Escherichia coli gsiB that encodes the periplasmic solute-binding protein of a glutathione transporter was amplified by PCR, and then inserted into a prokaryotic expression vector pWaldo-GFPe harboring GFP reporter gene through the method Sequence and Ligation-Independent Cloning (SLIC). The resulting recombinant plasmid pWaldo-GFP-GsiB was transformed into different E. coli strains and the expression conditions were optimized. It was found that E. coli BL21(DE3) was the best strain for gsiB gene expression among the four strains tested. Induction at lower incubation temperature of 18 degrees C and 0.1 mmol/L of IPTG led to higher expression of gsiB in E. coli BL21(DE3). Western blotting analysis also showed the expression of gsiB and the molecular weight of expressed protein as expected.

Zhang C.,National University of Ireland | Tang Y.,Sichuan University | Xu X.,University College Cork | Kiely G.,University College Cork
Applied Geochemistry | Year: 2011

It is challenging to perform spatial geochemical modelling due to the spatial heterogeneity features of geochemical variables. Meanwhile, high quality geochemical maps are needed for better environmental management. Soil organic C (SOC) distribution maps are required for improvements in soil management and for the estimation of C stocks at regional scales. This study investigates the use of a geographically weighted regression (GWR) method for the spatial modelling of SOC in Ireland. A total of 1310 samples of SOC data were extracted from the National Soil Database of Ireland. Environmental factors of rainfall, land cover and soil type were investigated and included as the independent variables to establish the GWR model. The GWR provided comparable and reasonable results with the other chosen methods of ordinary kriging (OK), inverse distance weighted (IDW) and multiple linear regression (MLR). The SOC map produced using the GWR model showed clear spatial patterns influenced by environmental factors and the smoothing effect of spatial interpolation was reduced. This study has demonstrated that GWR provides a promising method for spatial geochemical modelling of SOC and potentially other geochemical parameters. © 2011 Elsevier Ltd.

Jiang H.,Sichuan University
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2010

We studied the reduction of soluble and highly toxic selenite to elemental red selenium, under aerobic condition by Pseudomonas alcaliphila MBR, with organic carbon as electron donor. The strain could grow under pH 6-11 and resist to high concentration of selenite with the minimal inhibitory concentration of 50 mmol/L. After 5 days, the strain used sodium citrate as electron donor, and reduced 2.0 mmol/L selenite to elemental red selenium from the culture fluid, the elemental red selenium was stored outside the cells. The glutathione and nitrate could increase the number of reduction rate. This study implies the application of Pseudomonas alcaliphila MBR to convert selenite to elemental red selenium.

Xu F.,Southwest Petroleum University | Yi Z.,Sichuan University
Neurocomputing | Year: 2011

Motivated by Salinas's (2003) original discovery in [1] and inspired by Oja's (1982) seminal work in [2], in this paper, we propose a class of simplified background neural networks model with two subnetworks. Some basic dynamic properties including boundedness, global attractivity, stability, and complete convergence are analyzed rigorously. The main contributions in this paper are as follows: (1) The boundedness of the new model is verified and conditions for global attractivity are derived. (2) Conditions on asymptotically stable of equilibrium points are obtained. (3) Complete convergence for the new network is proved by constructing a novel energy function. Finally, numerical examples demonstrate our theoretical results. © 2011 Elsevier B.V.

Liu Y.,Sichuan University | Liu B.,Data Storage Institute Singapore | Ling S.H.,University of Technology, Sydney
Neurocomputing | Year: 2011

By the fixed-point theorem subject to different polyhedrons and some inequalities (e.g., the inequality resulted from quadratic programming), we obtain three theorems for the Lotka-Volterra recurrent neural networks having almost periodic coefficients and delays. One of the three theorems can only ensure the existence of an almost periodic solution, whose existence and uniqueness the other two theorems are about. By using Lyapunov function, the sufficient condition guaranteeing the global stability of the solution is presented. Furthermore, two numerical examples are employed to illustrate the feasibility and validity of the obtained criteria. Compared with known results, the networks model is novel, and the results are extended and improved. © 2010 Elsevier B.V.

Bergholz J.,Boston University | Xiao Z.-X.,Sichuan University
Cancer Microenvironment | Year: 2012

The p53-related protein p63 has pleiotropic functions, including cell proliferation, survival, apoptosis, differentiation, senescence, and aging. The p63 gene is expressed as multiple isoforms that either contain an N-terminal p53-homologous transactivation domain (TAp63) or that lack this domain (ΔNp63). Multiple studies have demonstrated that p63 plays a crucial role in stratified epithelial development, and have shown the importance of p63 for maintaining proliferation potential, inducing differentiation, and preventing senescence. Additionally, much research focuses on the role of p63 in cancer progression. Clinical evidence suggests that p63 may play a role in inhibiting metastasis. Similarly, genetic mice models together with cell culture data strongly indicate that p63 deficiency may be a causative factor for metastatic spread. Moreover, the role of p63 in cancer metastasis has been shown to be greatly related to the ability of mutant p53 to promote cancer malignancy. However, there is still much confusion as to what the role of each specific isoform is. In this review, we highlight some of the major findings in the current literature regarding the role of specific p63 isoforms in development, tumorigenesis, and particularly in cancer metastasis. © 2012 Springer Science+Business Media B.V.

Hu Y.,Beijing University of Chemical Technology | Zhao N.N.,Beijing University of Chemical Technology | Li J.S.,Sichuan University | Yang W.T.,Beijing University of Chemical Technology | Xu F.J.,Beijing University of Chemical Technology
Journal of Materials Chemistry | Year: 2012

The inherent hydroxyl groups on the porous polycaprolactone (PPCL) films (prepared by using poly(ethylene glycol) as the pore-forming agent) could be reacted with 2-bromoisobutyrate bromide to produce a sufficient concentration of surface-coupled atom transfer radical polymerization (ATRP) initiators for the subsequent surface-initiated ATRP of thermo-responsive N-isopropylacrylamide (NIPAAm) at room temperature. A kinetics study revealed that the chain growth of the grafted NIPAAm polymer (P(NIPAAm)) was very fast and consistent with a 'controlled' process. The graft copolymerization not only occurred on the porous film surface, but also took place into the film bulk. The resultant P(NIPAAm)-grafted PPCL (PPCL-g-P(NIPAAm)) films assumed a uniform and interconnected porous structure and exhibited a temperature-sensitive property with a lower critical solution temperature (LCST) of about 32 °C, not unlike pure P(NIPAAm). The release of bovine serum albumin (BSA as a model protein) from the PPCL-g-P(NIPAAm) films was characterized by an initial burst, followed by a sustained release. These thermo-responsive PPCL-g-P(NIPAAm) porous films are potentially useful in biomedical fields. This journal is © 2012 The Royal Society of Chemistry.

Fu Z.-W.,Sichuan University
Chinese Physics C | Year: 2015

Using a conventional constituent-quark model, I = 1/2 scalar κ, vector K∗(892), and axial vector K1 mesons are studied in the asqtad-improved staggered fermion with wall-source and point-sink interpolators. The mass ratio of mκ/mK∗(892) is numerically confirmed to apparently vary with quark mass, and the experimental ordering mK∗(892) >mκ holds elegantly when the light u/d quark masses are sufficiently small, while the valence strange quark mass is fixed to its physical value. We also get reasonable signals for the K1 meson suggested by the SCALAR Collaboration from lattice QCD. The computations are conducted with the MILC Nf = 3 flavor gauge configurations at three lattice spacings: a≈0.15, 0.12, and 0.09 fm.

Tao Y.,Stanford University | Cheung L.S.,Carnegie Institution for Science | Li S.,Stanford University | Li S.,Sichuan University | And 6 more authors.
Nature | Year: 2015

Eukaryotes rely on efficient distribution of energy and carbon skeletons between organs in the form of sugars. Glucose in animals and sucrose in plants serve as the dominant distribution forms. Cellular sugar uptake and release require vesicular and/or plasma membrane transport proteins. Humans and plants use proteins from three superfamilies for sugar translocation: the major facilitator superfamily (MFS), the sodium solute symporter family (SSF; only in the animal kingdom), and SWEETs. SWEETs carry mono- and disaccharides across vacuolar or plasma membranes. Plant SWEETs play key roles in sugar translocation between compartments, cells, and organs, notably in nectar secretion, phloem loading for long distance translocation, pollen nutrition, and seed filling. Plant SWEETs cause pathogen susceptibility possibly by sugar leakage from infected cells. The vacuolar Arabidopsis thaliana AtSWEET2 sequesters sugars in root vacuoles; loss-of-function mutants show increased susceptibility to Pythium infection. Here we show that its orthologue, the vacuolar glucose transporter OsSWEET2b from rice (Oryza sativa), consists of an asymmetrical pair of triple-helix bundles, connected by an inversion linker transmembrane helix (TM4) to create the translocation pathway. Structural and biochemical analyses show OsSWEET2b in an apparent inward (cytosolic) open state forming homomeric trimers. TM4 tightly interacts with the first triple-helix bundle within a protomer and mediates key contacts among protomers. Structure-guided mutagenesis of the close paralogue SWEET1 from Arabidopsis identified key residues in substrate translocation and protomer crosstalk. Insights into the structure-function relationship of SWEETs are valuable for understanding the transport mechanism of eukaryotic SWEETs and may be useful for engineering sugar flux. ©2015 Macmillan Publishers Limited. All rights reserved.

This study produced nano-porous titanium dioxide (TiO2) using two-step method, and on the basis of experimental materials, the study also made a resistance-type formaldehyde sensor whose base was made of aluminium oxide (Al2O3) ceramic. Besides, the study analyzed responding sensitivity, selectivity, stability and response recovery time of formaldehyde gas sensor as well as response mechanism of the sensor on formaldehyde (HCHO); meanwhile, the influence of humidity on gas sensitive response was also explored. In addition, equipment that had functions of Zigbee wireless transmission and detecting surrounding environment was installed in the building, and on the basis of application of ZigBee communication protocol in build environment monitoring and developed formaldehyde gas sensor, the study further explored wireless sensor nodes which could detect HCHO concentration in real time. Subordinate nodes were responsible for acquisition and transmission of data of HCHO concentration, temperature and humidity, while principle nodes were mainly responsible for controlling operating status of subordinate nodes and receiving and dis-playing data. Received data could be displayed on liquid crystal display (LCD) of principle nodes or be sent to upper computer for systematical analysis through universal serial bus (USB). Therefore, wireless sensor nodes could not only be used in gas sensitive tests, but also be used as a kind of portable indoor HCHO detector. Copyright © 2016 American Scientific Publishers All rights reserved.

He Y.,Sichuan University | Guo H.,Nanjing Southeast University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We propose a topological defect or instanton solution with nonzero Hopf invariant to the 3+1D non-Abelian gauge theory coupled with scalar fields. This solution, which we call Hopf defect, represents a spacetime event that makes a 2. π rotation of vacuum manifold of the monopole. Although the action of this Hopf defect is logarithmically divergent, it may still give relevant contributions in a finite-sized system. Since the Chern-Simons term for the unbroken U(1) gauge field may appear in the low energy effective theory, the Hopf defect may possibly generate a phase factor change for the monopoles. © 2014 The Authors.

Li Y.,Sichuan University
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2010

TNF-related apoptosis-inducing ligand (TRAIL) is a member of factor TNF family, which could be potentially developed as novel antitumor agent due to its selective and efficient induction of apoptosis in tumor cells. Gene recombinant expression is an important tool for production of pharmaceutical protein. In this paper, the gene encoding human soluble TRAIL (114-281aa fragment) was cloned by PCR and then inserted into the Pichia Pastoris expression vector pPIC9K. The transformants were double-screened on plates containing neomycin G418 and many clones with high levels of G418-resistance were selected for further studies on protein expression. The recombinant human soluble TRAIL was secreted into the BMMY media under the condition of 3% methanol. And the recombinant protein was purified to homogeneity (-80% purity) by using Ni-agarose affinity chromatography. The yield of this protein is about 1-2 mg per liter culture. Cell viability assays demonstrated that human soluble TRAIL was cytotoxic in both leukemia cells Jurkat and lung cancer cells A549. After treatment with 0.05 microg/ml TRAIL, the survival rate of Jurkat cells was about 10%. The expressed TRAIL showed dose-dependent cytotoxicity in A549 cells within the range of 0.1-1 microg/ml. When the protein concentration reached 1 microg/ml, the survival rates of A549 cells were about 30%. However, the recombinant human soluble TRAIL did not show obvious cytotoxicity in human skin fibroblast cells (HSF) at concentrations tested. There results demonstrate that human soluble TRAIL is selectively cytotoxic in tumor cells. The expression system constructed in this experiment might contribute to further production of soluble TRAIL and TRAIL-based novel fusion proteins in large quantities.

Lourembam J.,Nanyang Technological University | Wu J.,Sichuan University | Ding J.,King Abdullah University of Science and Technology | Lin W.,Nanyang Technological University | Wu T.,King Abdullah University of Science and Technology
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

In this paper, we investigate the electric field effect on epitaxial Pr0.65(Ca0.75Sr0.25)0.35MnO3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides. © 2014 American Physical Society.

Fu Z.,Sichuan University
International Journal of Modern Physics A | Year: 2013

Using the lattice simulations we measure the point-to-point κ correlators in the Asqtad-improved staggered fermion formulation with the sufficiently light u/d quark. We then analyze these correlators using the rooted staggered chiral perturbation theory (rSχPT). After the chiral extrapolation, we obtain the physical κ mass with 835±93 MeV, which is in agreement with the recent BES experimental values. These numerical simulations are carried out with the MILC Nf = 2+1 flavor fine gauge configurations at a lattice spacing of a ≈0.09 fm. © 2013 World Scientific Publishing Company.

Zhu W.,University of Sichuan | Liu D.,Sichuan University | Ai H.,University of Sichuan
ACS Applied Materials and Interfaces | Year: 2014

A dual-channel naphthalimide-based chemosensor for rapid and sensitive detection of fluoride ion has been developed. Upon addition of F-, it undergoes deprotonation reaction through H-bonding interactions, and its maximum absorption wavelength is red-shifted for 214 nm to the far-red region, together with drastically quenched fluorescence. In addition, it shows high selectivity toward F- anion, thus could be used for practical applications to detecting F- in both solution and solid state. Furthermore, the fluorescence of NIM could be enhanced in protein-containing acidic environments, hence NIM could act as lysosome marker to differentiate cancer cells from normal ones in cell imaging. © 2014 American Chemical Society.

Wei J.,University of Sichuan | Ju X.-J.,University of Sichuan | Zou X.-Y.,University of Sichuan | Xie R.,University of Sichuan | And 4 more authors.
Advanced Functional Materials | Year: 2014

Novel multi-stimuli-responsive microcapsules with adjustable controlled-release characteristics are prepared by a microfluidic technique. The proposed microcapsules are composed of crosslinked chitosan acting as pH-responsive capsule membrane, embedded magnetic nanoparticles to realize "site-specific targeting", and embedded temperature-responsive sub-microspheres serving as "micro-valves". By applying an external magnetic field, the prepared smart microcapsules can achieve targeting aggregation at specific sites. Due to acid-induced swelling of the capsule membranes, the microcapsules exhibit higher release rate at specific acidic sites compared to that at normal sites with physiological pH. More importantly, through controlling the hydrodynamic size of sub-microsphere "micro-valves" by regulating the environment temperature, the release rate of drug molecules from the microcapsules can be flexibly adjusted. This kind of multi-stimuli-responsive microcapsules with site-specific targeting and adjustable controlled-release characteristics provides a new mode for designing "intelligent" controlled-release systems and is expected to realize more rational drug administration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

A proposal by Lüscher enables us to extract the elastic scattering phases from two-particle energy spectrum in a cubic box using lattice simulations. Rummukainen and Gottlieb further extend it to the moving frame, which is devoted to the system of two identical particles. In this work, we generalize Rummukainen-Gottlieb's formula to the generic two-particle states where two particles are explicitly distinguishable, namely, the masses of the two particles are different. Their relations with the elastic scattering phases of two-particle energy spectrum in the continuum are obtained for both C 4v and C 2v symmetries. Our analytical results will be very helpful for the study of some resonances, such as kappa, vector kaon, and so on. © 2012 American Physical Society.

Kwang-Hua C.W.,Sichuan University
Canadian Journal of Physics | Year: 2013

Possible onset of the quantum plasticity in soft-solid He-4 was discovered recently in 7 nm diameter (Vycor glass) nanopores. Here, by using the transition-state model together with the specific activation energy and activation volume, we investigated the possible frictionless plastic flows of soft-solid He-4 under high pressure in confined nanodomains and we observed a series of sudden changes in the shearing stresses at corresponding very high shear strain rates of (locally amorphous) soft-solid He-4 for different activation volumes considering the role of He-3 impurities. Our calculated critical velocity for a fixed concentration of He-3 quantitatively agrees with recent reported values. © 2013 Published by NRC Research Press.

Fu H.Y.,Sichuan University | Doucet H.,CNRS Chemistry Institute of Rennes
European Journal of Organic Chemistry | Year: 2011

The palladium-catalysed direct arylation of methyl 2-furoate with aryl bromides was studied. The use of KOAc as the base, dimethylacetamide (DMAc) as the solvent and Pd(OAc) 2 as the catalyst was found to give 5-arylfurans regioselectively and without decarboxylation. These methyl 5-aryl-2-furoates gave 2,5-diarylfurans by decarboxylative coupling by using Pd(OAc) 2 as the catalyst. Methyl 2-furoate thus represents a convenient alternative substrate to furan for the synthesis of mono- or poly-arylated furans. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The s-wave pion-kaon (πK) scattering lengths at zero momentum are calculated in lattice QCD with sufficiently light u/d quarks and strange quark at its physical value by the finite size formula. The light quark masses correspond to m π=0.330-0.466GeV. In the Asqtad improved staggered fermion formulation, we measure the πK four-point correlators for both the isospin I=1/2 and 3/2 channels, and analyze the lattice simulation data at the next-to-leading order in the continuum three-flavor chiral perturbation theory, which enables a simultaneous extrapolation of πK scattering lengths at the physical point. We adopt a technique with the moving wall sources without gauge fixing to obtain substantiable accuracy; moreover, for the I=1/2 channel, we employ the variational method to isolate the contamination from the excited states. Extrapolating to the physical point yields the scattering lengths as m πa 3/2=-0.0512(18) and m πa 1/2=0.1819(35) for the I=3/2 and 1/2 channels, respectively. Our simulation results for πK scattering lengths are in agreement with the experimental reports and theoretical predictions, and can be comparable with other lattice simulations. These simulations are carried out with MILC N f=2+1 flavor gauge configurations at lattice spacing 0.15fm. © 2012 American Physical Society.

Li L.,University of Sichuan | Liu C.,University of Sichuan | Wang Q.-H.,University of Sichuan | Wang Q.-H.,Sichuan University
Optics Letters | Year: 2012

We propose an optical switch based on the electrowetting effect. A transparent oil and a dye-doped water fill a cell. The two liquids are immiscible and form a curved interface. A transparent pillar-shaped platform with a round dome is fixed on the substrate. The dome of the platform is submerged in the water. As a result, light is highly absorbed by the covered water. When the shape of the water is changed, the oil can touch the dome of the platform due to the electrowetting effect. Then the transparent platform and the oil form a channel which can pass through the incident light. Our results show that the system can obtain a high optical attenuation (̃928:1) and reasonable response time (̃47 ms). The diameter of the aperture can be tuned from 0 to ̃3.0 mm. The proposed optical switch has potential application in light shutters, variable optical attenuators, and adaptive irises. © 2012 Optical Society of America.

Fu Z.,Sichuan University | Fu K.,Tsinghua University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We deliver an exploratory lattice QCD examination of the K *(892) meson decay width via the p-wave scattering phase shift of a pion-kaon (πK) system in the isospin I=1/2 channel. The modified Rummukainen-Gottlieb formula for a two-particle system with arbitrary mass is employed to extract phase shifts, which clearly reveal the existence of a resonance at a mass around the K *(892) meson mass. The effective range formula is applied to describe the energy dependence of the phase shift and we extract the effective K *→πK coupling constant as g K*πK=6.38(78). The decay width estimated from the phase shift is about 64.9±8.0MeV, which is in reasonable accordance with the experiment. Our lattice investigations are conducted on a 203×48 MILC gauge configuration with the N f=2+1 flavors of the asqtad-improved staggered dynamical sea quarks at (m π+m K)/m K *0.739 and lattice spacing a0.15fm. © 2012 American Physical Society.

Yuan L.,Sichuan University
Lecture Notes in Electrical Engineering | Year: 2014

Processor technology is advancing from bus-based multicores to network- on-chip-based many-cores, posting new challenges for operating system design. In this paper, we present the trends in computer architecture that will affect operating system design, and summarize three concrete challenges for operating system design coming with these trends. In the end, we propose a new operating system architecture, Chameleon, to meet these challenges. © Springer-Verlag Berlin Heidelberg 2014.

Tang B.,Chongqing University | Song T.,Chongqing University | Li F.,Sichuan University | Deng L.,Chongqing University
Renewable Energy | Year: 2014

Fault diagnosis for wind turbine transmission systems is an important task for reducing their maintenance cost. However, the non-stationary dynamic operating conditions of wind turbines pose a challenge to fault diagnosis for wind turbine transmission systems. In this paper, a novel fault diagnosis method based on manifold learning and Shannon wavelet support vector machine is proposed for wind turbine transmission systems. Firstly, mixed-domain features are extracted to construct a high-dimensional feature set characterizing the properties of non-stationary vibration signals from wind turbine transmission systems. Moreover, an effective manifold learning algorithm with non-linear dimensionality reduction capability, orthogonal neighborhood preserving embedding (ONPE), is applied to compress the high-dimensional feature set into low-dimensional eigenvectors. Finally, the low-dimensional eigenvectors are inputted into a Shannon wavelet support vector machine (SWSVM) to recognize faults. The performance of the proposed method was proved by successful fault diagnosis application in a wind turbine's gearbox. The application results indicated that the proposed method improved the accuracy of fault diagnosis. © 2013 Elsevier Ltd.

Su Y.,University of Sichuan | Lv Y.,Sichuan University
RSC Advances | Year: 2014

Due to the high surface area, excellent conductivity, high mechanical strength, and good biocompatibility, graphene has become a growing area of interest since it was first discovered in 2004. Despite these important achievements in the design of fluorescent, colorimetric and electrochemical sensors, the merging of graphene and chemiluminescence (CL) or electrochemiluminescence (ECL), especially CL is still in its infancy. In this review, according to the roles that graphene and its derivatives play in various CL or ECL systems, we discuss the new CL and ECL sensors in particular, in the last two years. Furthermore, we discuss some future prospects and critical challenges in this field. Additionally, possible solutions to overcome these challenges are presented. © 2014 The Royal Society of Chemistry.

Liu J.-Q.,Sichuan University | Duan Y.-W.,CAS Kunming Institute of Botany | Hao G.,South China Agricultural University | Ge X.-J.,CAS South China Botanical Garden | Sun H.,CAS Kunming Institute of Botany
Journal of Systematics and Evolution | Year: 2014

As the highest and largest plateau in the world, the Qinghai-Tibet Plateau, with its numerous endemic species, is one of the important alpine biodiversity hotspots. Only recently have the evolutionary histories and underlying adaptations of these alpine plants become clear, through research mostly based on testable experiments and analyses. In this issue, we collected a total of 13 papers related to such aims. In addition, we selected a few published papers to highlight the major findings in the recent past. We also outlined the outlook and direction of future research. © 2014 Institute of Botany, Chinese Academy of Sciences.

Wang Y.,CAS Nanjing Institute of Geology and Palaeontology | Huang C.,Sichuan University | Sun B.,Lanzhou University | Quan C.,Jilin University | And 3 more authors.
Earth-Science Reviews | Year: 2014

The Cretaceous was one of the most remarkable periods in geological history, with a "greenhouse" climate and several important geological events. Reconstructions of atmospheric CO2 using proxies are crucial for understanding the Cretaceous "greenhouse." In this paper we summarize the major approaches for reconstructing CO2 based on paleobotanical or geochemical data, and synthesize the CO2 variations throughout the Cretaceous. The results show that atmospheric CO2 levels remained relatively high throughout the Cretaceous, but were lower in the early Cretaceous, highest in the mid-Cretaceous and gradually declined during the late Cretaceous. However, this overall trend was interrupted by several rapid changes associated with ocean anoxic events (OAEs) and the end-Cretaceous catastrophic event. New data on paleo-CO2 levels from paleobotanical and paleosol evidences support not only the overall trends indicated by geochemical models, but provide more precise records of the short-term fluctuations related to brief episodes of climate change. Temporal resolution within the long quiet magnetic period in the middle Cretaceous is one of the obstacles preventing us from a more comprehensive understanding of the CO2 climate linkage. But new paleo-CO2 determinations and climatic data from stratigraphic sections of sediments intercalated with datable volcanic rocks will allow a better understanding of the relationships between fluctuations of atmospheric CO2, climate change, and geological events. © 2013 Elsevier B.V.

Xu D.,Sichuan University | Cui Q.,University of Wisconsin - Madison | Guo H.,University of New Mexico
International Reviews in Physical Chemistry | Year: 2014

Metallo-enzymes play an indispensible role in many biological functions, and their modes of substrate binding and catalysis differ considerably from those of metal-free enzymes. A thorough understanding of the catalytic mechanisms of these enzymes cannot be achieved with experiments alone. In this review, recent theoretical investigations of the structure, binding, and catalysis of zinc hydrolases, which cleave substrate C-N and C-O bonds with high efficiency, are surveyed. Particular attention is paid to several extensively studied zinc peptidases as well as metallo-β-lactamases, which are responsible for ever-increasing bacterial resistance to penicillin-based antibiotics. These studies, particularly the ones using quantum mechanical/molecular mechanical methods, provide valuable insights into metal/ligand interactions, substrate binding and catalysis of these important metallo-enzymes. © 2014 © 2014 Taylor & Francis.

Hu X.,Sichuan University
Guangxue Xuebao/Acta Optica Sinica | Year: 2010

Effects of external cavity's feedback light on length of internal cavity and the photon state density in internal cavity are investigated, and effects of self mixing interference are discussed in detail. The results demostrate that, external cavity's feedback light not only changes front facet reflectivity of Fabry-Perot cavity, but also cause discontinuous variation of equivalent length of internal cavity, and then photon state density in internal cavity also discontinuously varies. So that, the external feedback light makes quantum efficiency continuously and discontinuously vary. Also gain coefficient and saturated light intensity vary continuously and discontinuously. Also self-mixing interference signal does not change discontinuously with the complex cavity modes produced by external cavity's feedback light, and effect of external cavity's feedback light on charge carrier lifetime is very small. External cavity's feedback light evidently reduces radiative recombination lifetime of charge carrier, raises radiative recombination efficiency and weakens non-radiative recombination efficiency.

Ren H.-S.,University of Sichuan | Li Y.-K.,University of Sichuan | Zhu Q.,University of Sichuan | Zhu J.,Sichuan University | Li X.-Y.,University of Sichuan
Physical Chemistry Chemical Physics | Year: 2012

According to our recent studies on the nonequilibrium solvation, the solvent reorganization energy is found to be the cost of maintaining the residual polarization P′, which equilibrates with the extra electric field Eex. On the basis of this solvent reorganization energy and the well-established equilibrium solvation energy, a novel and reasonable expression for the spectral shift of the electronic absorption spectra is proposed in this work. Furthermore, the two lowest transitions of uracil in aqueous solution are investigated as test cases with the TDDFT/6-311++G** method. The obtained spectral shift is 0.48 eV for n → π* transition and -0.14 eV for π → π* transition, agreeing well with available experimental results. The contributions to the shift are discussed and the electrostatic plus polarization components are found to be crucial for the electronic absorption spectra of uracil in aqueous solution. © 2012 the Owner Societies.

Huang X.,University of Sichuan | Li L.,University of Sichuan | Liao X.,University of Sichuan | Shi B.,Sichuan University
Journal of Molecular Catalysis A: Chemical | Year: 2010

Bayberry tannin (BT), a natural plant polyphenol, was used as a stabilizer to prepare supported platinum catalysts. Bayberry tannin was first grafted onto aminated SiO2 beads and subsequently coordinate with Pt(IV) species. Then a series of heterogeneous Pt-bayberry tannin-SiO2 (Pt-BT-SiO2) catalysts was obtained after reduction with NaBH4. The catalysts were characterized by UV-DR, XRD and TEM, and the coordination state of Pt(IV) with BT grafted on SiO2 beads was investigated by XPS. It was found that the Pt-BT-SiO2 catalysts were highly active and stable in aqueous hydrogenation of acrylic acid, α-methacrylic acid, allyl alcohol and 2-methyl-3-buten-2-ol. Moreover, the Pt-BT-SiO2 catalysts could be conveniently recovered from the reaction systems simply by filtration, and be reused at least five times without loss of activity. Crown Copyright © 2010.

Tang D.,Center for Molecular Design | Chen Z.,Haimen Wisdom Pharmaceutical Co. | Hu J.,Center for Molecular Design | Sun G.,Center for Molecular Design | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

The mechanism of the CO oxidation promoted by a neutral Ag55 cluster was investigated extensively, using density functional theory calculations. The CO oxidation process catalyzed by anionic and cationic Ag 55 clusters was also studied, to clarify the effects of the charge state. The Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms were discussed in detail. Six reaction pathways were found for the Ag 55-mediated CO oxidation. It was found that the ER mechanism competed with the LH mechanism. The rate-limiting step of the CO oxidation was the reaction of CO with the Ag55O species. All of the anionic, neutral, and cationic Ag55 clusters were able to promote CO oxidation at low temperatures. The present results enrich our understanding of the catalytic oxidation of CO by nano-sized Ag-based catalysts. © 2012 the Owner Societies.

He Y.,James Franck Institute | He Y.,Sichuan University | Levin K.,James Franck Institute
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We address conservation laws associated with current, momentum, and energy and show how they can be satisfied within many body theories which focus on pair correlations. Of interest are two well known T-matrix theories which represent many body theories which incorporate pairing in the normal state. The first of these is associated with the Nozieres Schmitt-Rink theory, while the second involves the T matrix of a BCS-Leggett-like state as identified by Kadanoff and Martin. T-matrix theories begin with an ansatz for the single particle self energy and are to be distinguished from Φ-derivable theories which introduce an ansatz for a particular contribution to the thermodynamical potential. Conservation laws are equivalent to Ward identities which we address in some detail here. Although Φ-derivable theories are often referred to as "conserving theories," a consequence of this work is the demonstration that these two T-matrix approaches similarly can be made to obey all conservation laws. When simplifying approximations are made in Φ-derivable or other theories, one has to take care that the end results are not incompatible with conservation. © 2014 American Physical Society.

He Y.,Sichuan University | Lee P.A.,Massachusetts Institute of Technology | Varma C.M.,University of California at Riverside
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We show that a finite Hall effect in zero applied magnetic field occurs for partially filled bands in certain time-reversal violating states with zero net flux per unit cell. These states are the Magneto-chiral states with parameters in the effective one-particle Hamiltonian such that they do not satisfy the Haldane-type constraints for topological electronic states. The results extend an earlier discussion of the Kerr effect observed in the cuprates but may be applicable to other experimental situations. © 2014 American Physical Society.

Mei Y.,Mianyang Normal University | Mei Y.,CAEP - China Academy of Engineering Physics | Zheng W.-C.,Sichuan University | Zhang L.,CAEP - China Academy of Engineering Physics
Optical Materials | Year: 2013

Three optical band positions and four spin-Hamiltonian (or EPR) parameters (g factors g//, g⊥ and hyperfine structure constants A//, A⊥) of two tetragonal Cu2+ centers in Cu2+-doped ZnO nanocrystals synthesized at room temperature by mild and simple solution method are calculated from the complete diagonalization (or energy matrix) method based on the cluster approach (where the covalence effect due to the admixture between the orbitals of dn ion and ligands is considered). The calculations rest on the defect models suggested in the previous paper that both Cu 2+ centers are Cu2+ on the interstitial octahedral sites in ZnO nanocrystals and the tetragonal elongations of octahedra are due to the static Jahn-Teller effect. The calculated results are in reasonable agreement with the experimental values. The defect models of both Cu2+ centers are therefore confirmed and their defect structures (i.e., the tetragonal elongations R//-R⊥) are acquired. The results are discussed. © 2013 Elsevier B.V. All rights reserved.

Gou J.,University of Electronic Science and Technology of China | Yi Z.,Sichuan University | Du L.,Australian National University | Xiong T.,University of Electronic Science and Technology of China
Computer Journal | Year: 2012

K-nearest neighbor (KNN) rule is a simple and effective algorithm in pattern classification. In this article, we propose a local mean-based k-nearest centroid neighbor classifier that assigns to each query pattern a class label with nearest local centroid mean vector so as to improve the classification performance. The proposed scheme not only takes into account the proximity and spatial distribution of k neighbors, but also utilizes the local mean vector of k neighbors from each class in making classification decision. In the proposed classifier, a local mean vector of k nearest centroid neighbors from each class for a query pattern is well positioned to sufficiently capture the class distribution information. In order to investigate the classification behavior of the proposed classifier, we conduct extensive experiments on the real and synthetic data sets in terms of the classification error. Experimental results demonstrate that our proposed method performs significantly well, particularly in the small sample size cases, compared with the state-of-the-art KNN-based algorithms. © 2011 The Author. Published by Oxford University Press on behalf of The British Computer Society. All rights reserved.

Song B.,CAS Shanghai Institute of Applied Physics | Yang J.,Sichuan University | Zhao J.,Dalian University of Technology | Fang H.,CAS Shanghai Institute of Applied Physics
Energy and Environmental Science | Year: 2011

The intercalation and diffusion of lithium ions in a bundle of carbon nanotubes (CNTs) are investigated via an ab initio molecular dynamics simulation method based on the density functional theory. We found that lithium ions quickly penetrate into the CNTs and the space between neighboring CNTs. With a low Li ion density, the Li ions tend to stay close to the nanotube ends. Interestingly, Li ions are able to penetrate through the carbon nanotube and move from one end to the other. We also discovered that Li ions may remain between two neighboring CNTs, which presents a new approach for Li ion intercalation and storage. Importantly, Li ions located among three neighboring CNTs have very strong adsorption potentials that are a factor of four larger than those of Li ions located along the central axis of a single-walled nanotube (SWNT). This indicates that Li ions located among three neighboring CNTs would be very difficult to remove from a nanotube bundle, which suggests that Li storage capacity in this case is possibly irreversible, and that keeping the nanotubes apart with an appropriate distance would hinder or promote the formation of irreversible intercalation. Our findings contribute to the understanding of lithium intercalation and diffusion in CNTs, which has implications for the experimental development and application of rechargeable Li ion batteries. © 2011 The Royal Society of Chemistry.

Li L.,University of Sichuan | Liu C.,University of Sichuan | Ren H.,Chonbuk National University | Wang Q.-H.,University of Sichuan | Wang Q.-H.,Sichuan University
Optics Letters | Year: 2013

We report a tunable iris using two immiscible liquids. One liquid is opaque and conductive, while the other liquid is clear and insulating. The opaque liquid forms an iris-like opening in its central area on one glass substrate surface. The clear liquid is used to fill the outside space of the opaque liquid. In the voltage-off state, the opening presents the smallest aperture. When a voltage is applied to the liquids, the diameter of the iris is enlarged due to the electro-wetting effect. Our results show that the aperture of the iris can be tuned from ∼2.3 to ∼6.1 mm as the applied voltage is changed from 0 to ∼65 V. The response time and the transmittance in the opening area were measured to be ∼200 ms and ∼85%, respectively. Our adaptive iris has potential applications in beam controls, light shutters, and lab-on-a-chip devices. © 2013 Optical Society of America.

Wang Y.,Sichuan University
Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi | Year: 2010

To study the infection status and the molecular characteristics of Vibrio parahaemolyticus isolated from diarrheal patients in Shenzhen, in 2007 to 2008 and to provide evidence for the prevention and control of diarrheal diseases caused by Vibrio parahaemolyticus. More than 80 fecal specimens from four sentinel surveillance hospitals were collected and cultured each month. A total of 361 isolates of Vibrio parahaemolyticus were sero-typed and examined by real-time PCR for the presence of two major virulence genes, tdh and trh. Of 361 strains, 60 O3: K6 strains isolated from six suspected outbreaks in August, 2007 and in September, 2008 were typed by pulsed-field gel electrophoresis (PFGE). 4384 stool samples were detected in four sentinel surveillance hospitals and with 361 Vibrio parahaemolyticus strains isolated that belonged to 28 serotypes. Serotype O3:K6, O4:K8 and O1:KUT accounted for 67.90%, 7.50% and 6.10%, respectively. Of 361 strains, 337 strains belonged to tdh+trh-, 11 strains were tdh-trh- and 13 strains were tdh+trh+. The most prevalent serotype which caused diarrheal diseases was tdh+trh in Shenzhen. The 60 isolates were discriminated into twenty different PFGE patterns, which belonged to three clones. Among the 60 isolates, most of the PFGE patterns of isolates from the suspected outbreak locations were identical and some strains isolated from different year were different. Vibrio parahaemolyticus isolates in Shenzhen were dominated by O3:K6 strains. Most of these isolates carried tdh gene and few carried trh gene. Meanwhile, the identical patterns of isolates from 6 suspected outbreaks locations demonstrated that Vibrio parahaemolyticus outbreaks occurred in July 2007 and in September 2008 in Shenzhen. However, the dominated strains' PFGE patterns were different each year, indicating that the sources of Vibrio parahaemolyticus had a multiplex nature and the multiplex sources such as water, sea food and pickled products should be integrated monitored. Laboratory based surveillance of diarrheal diseases could contribute in establishing early warning system for the better prevention and control of diarrheal diseases.

Luo Y.B.,Sichuan University
Applied Mechanics and Materials | Year: 2014

Organic/inorganic nanocomposites have been widely focused because of their special properties. By modifying nano TiO2 and polylactic acid (PLA) with lactic acid, PLA/TiO2 nanocomposites was prepared, and the test on the dynamic mechanical property, thermal property, and thermal deformation temperature showed that adding nano TiO2 helped improve PLA's mechanics property, thermal decomposition temperature, and thermal deformation temperature to certain extent. © (2014) Trans Tech Publications, Switzerland.

Liu J.,Sichuan University
International journal of nanomedicine | Year: 2011

A nanoscale injectable in situ-forming hydrogel drug delivery system was developed in this study. The system was based on a self-assembling peptide RADA16 solution, which can spontaneously form a hydrogel rapidly under physiological conditions. We used the RADA16 hydrogel for the controlled release of paclitaxel (PTX), a hydrophobic antitumor drug. The RADA16-PTX suspension was prepared simply by magnetic stirring, followed by atomic force microscopy, circular dichroism analysis, dynamic light scattering, rheological analysis, an in vitro release assay, and a cell viability test. The results indicated that RADA16 and PTX can interact with each other and that the amphiphilic peptide was able to stabilize hydrophobic drugs in aqueous solution. The particle size of PTX was markedly decreased in the RADA16 solution compared with its size in water. The RADA16-PTX suspension could form a hydrogel in culture medium, and the elasticity of the hydrogel showed a positive correlation with peptide concentration. In vitro release measurements indicated that hydrogels with a higher peptide concentration had a longer half-release time. The RADA16-PTX hydrogel could effectively inhibit the growth of the breast cancer cell line, MDA-MB-435S, in vitro, and hydrogels with higher peptide concentrations were more effective at inhibiting tumor cell proliferation. The RADA16-PTX hydrogel was effective at controlling the release of PTX and inhibiting tumor cell growth in vitro. Self-assembling peptide hydrogels may work well as a system for drug delivery.

Xiang Y.,Deakin University | Natgunanathan I.,Deakin University | Peng D.,Sichuan University | Zhou W.,Deakin University | Yu S.,Deakin University
IEEE Transactions on Information Forensics and Security | Year: 2012

This work proposes a novel dual-channel time-spread echo method for audio watermarking, aiming to improve robustness and perceptual quality. At the embedding stage, the host audio signal is divided into two subsignals, which are considered to be signals obtained from two virtual audio channels. The watermarks are implanted into the two subsignals simultaneously. Then the subsignals embedded with watermarks are combined to form the watermarked signal. At the decoding stage, the watermarked signal is split up into two watermarked subsignals. The similarity of the cepstra corresponding to the watermarked subsignals is exploited to extract the embedded watermarks. Moreover, if a properly designed colored pseudonoise sequence is used, the large peaks of its auto-correlation function can be utilized to further enhance the performance of watermark extraction. Compared with the existing time-spread echo-based schemes, the proposed method is more robust to attacks and has higher imperceptibility. The effectiveness of our method is demonstrated by simulation results. © 2006 IEEE.

Huang H.,Ewha Womans University | Huang H.,Shandong University of Technology | Nandhakumar R.,Karunya University | Choi M.,Ewha Womans University | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

The chiral ketone (S)-3 shows high kinetic enantioselectivities toward the l form for general underivatized amino acids with hydrophobic side chains and a high thermodynamic enantioselectivity toward the d form for cysteine with its -SH polar side chain when used as an extractant in enantioselective liquid-liquid extractions in the presence of Aliquat 336. Consecutive extractions by imine formation and hydrolysis increase the enantiopurity of the amino acid, as both of these reactions are l-form-selective. © 2013 American Chemical Society.

Zhu L.,Sichuan University | Hwa R.C.,University of Oregon
Physical Review C - Nuclear Physics | Year: 2013

In the study of hadron production in Au-Au collisions at the BNL Relativistic Heavy-Ion Collider (RHIC), minijets play an important role in generating shower partons in the intermediate pT region. Momentum degradation of the hard and semihard partons as they traverse the inhomogeneous medium at various azimuthal angles results in a complicated convolution of geometrical, nuclear, and dynamical factors that cannot usually be described in a transparent way. In this work a compact formula is found that represents the inclusive distributions of minijets of any parton type at the surface of the medium for any collision centrality. They take into account the contributions from all initiating partons created at any point in the medium. By comparing with the case of no energy loss, a ratio has been determined that is analogous to the nuclear modification factor for minijets. Phenomenological reality of such distributions is examined by calculating the hadronization of the minijets in the recombination model. Good fits of the data on pion, kaon and proton production throughout the intermediate pT region have been obtained by adjusting the parameters controlling the magnitude of the thermal partons and the degradation rates of the semihard partons. The result gives support to the minijet spectra at any centrality on the one hand, and the hadronization procedure used on the other. An important property made manifest in this study is that quarks and gluons must not lose energy in the same way because the partons form mesons and baryons differently by recombination and the momenta of quarks and gluons must be degraded at different rates in order to reproduce the experimental pion and proton spectra. This is a feature that renders invalid the notion of parton-hadron duality or other hadronization schemes based on similar ideas. © 2013 American Physical Society.

Jiang Q.,Sichuan University | Wong A.O.L.,University of Hong Kong
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2014

Somatostain (SS) is known to inhibit growth hormone (GH) and prolactin (PRL) secretion. Somatolactin (SL) is a member of the GH/PRL family, but its regulation by goldfish brain somatostatin-28 (gbSS-28) has not been examined. To this end, the structural identity of goldfish SLα was established by 5'/3'-rapid amplification of cDNA ends. As revealed by in situ hybridization and immunohistochemical staining, the expression of SL isoforms was detected in pituitary cells located in the neurointermediate lobe (NIL). The transcripts of goldfish SS receptor 5a (Sst5a) but not Sst1b, Sst2, or Sst3a were detected in the goldfish NIL cells by RT-PCR. In goldfish pituitary cells, gbSS-28 not only had an inhibitory effect on basal SLα and SLβ mRNA levels but also could abolish insulin-like growth factor-stimulated SL gene expression. In primary cultures of goldfish NIL cells, gbSS-28 reduced forskolin-stimulated total cAMP production. With the use of a pharmacological approach, the adenylate cyclase (AC)/cAMP and phos-pholipase C (PLC)/inositol trisphosphate (IP3)/protein kinase C (PKC) cascades were shown to be involved in gbSS-28-inhibited SLα mRNA expression. Similar postreceptor signaling cascades were also observed for gbSS-28-reduced SLβ mRNA expression, except that PKC coupling to PLC was not involved. These results provide evidence that gbSS-28 can inhibit SLα and SLβ gene expression at the goldfish pituitary level via Sst5 through differential coupling of AC/cAMP and PLC/IP3/PKC cascades. © 2014 the American Physiological Society.

Wang W.,University of Sichuan | Zhang M.-J.,University of Sichuan | Chu L.-Y.,University of Sichuan | Chu L.-Y.,Sichuan University
Accounts of Chemical Research | Year: 2014

Functional polymeric microparticles with typical sizes of 1-1000 μm have received considerable attention for many applications. Especially in biomedical fields, polymeric microparticles with advanced functions such as targeted delivery, controlled encapsulation, or "capture and release" show great importance as delivery systems for active molecules and drugs, as imaging agents for analytics and diagnostics, as microreactors for confined bioreactions, and more. Generally, the functions of these microparticles rely on both their structures and the properties of their component materials. Thus, creating unique structures from functional materials provides an important strategy for developing advanced functional polymeric microparticles.Several methods, such as dispersion polymerization, precipitation polymerization, copolymer self-assembly, and phase-separated polymer precipitation can be used to make functional microparticles, but each has limitations, for example, their limited control over the particle size and structure. Using emulsions as templates, however, allows precise control over the size, shape, composition, and structure of the resulting microparticles by tuning those of the emulsions via specific emulsification techniques. Microfluidic methods offer excellent control of emulsion droplets, thereby providing a powerful platform for continuous, reproducible, scalable production of polymeric microparticles with unprecedented control over their monodispersity, structures, and compositions. This approach provides broad opportunities for producing polymeric microparticles with novel structure-property combinations and elaborately designed functions.In this Account, we highlight recent efforts in microfluidic fabrication of advanced polymeric microparticles with well-designed functions for potential biomedical applications, and we describe the development of microfluidic techniques for producing monodisperse and versatile emulsion templates. We begin by describing microparticles made from single emulsions and then describe those from complex multiple emulsions, showing how the resulting microparticles combine novel structures and material properties to achieve their advanced functions. Monodisperse emulsions enable production of highly uniform microparticles of desired sizes to achieve programmed release rates and passive targeting for drug delivery and diagnostic imaging. Phase-separated multiple emulsions allow combination of a variety of functional materials to generate compartmental microparticles including hollow, core-shell, multicore-shell, and hole-shell structures for controlled encapsulation and release, selective capture, and confined bioreaction. We envision that the versatility of microfluidics for microparticle synthesis could open new frontiers and provide promising and exciting opportunities for fabricating new functional microparticles with broad implications for myriad fields. © 2013 American Chemical Society.

Wang K.,Sichuan University
International Journal of Simulation: Systems, Science and Technology | Year: 2015

To control the training load of football players in a more scientific and reasonable way. Method: Establishing the football training load monitoring system based on ultra wideband (UWB) technology. Process: The article introduced the meaning and advantages of UWB technology, established a model of soccer training load monitoring system based on UWB technology, and displayed the development trend of scientific training monitoring mode of the future football. Result &Analysis: This article used the mathematical theory to elaborate the established monitor system model, carried out data statistics and analysis of the application of this model in soccer training, and found that this monitoring system can supply scientific and reasonable sports data and physical condition information of the football players for the coaches. Result: The football training load monitoring system based on UWB technology can effectively monitor the training load of football players. © 2015, UK Simulation Society. All rights reserved.

Xu J.,Sichuan University
Journal of Physics A: Mathematical and Theoretical | Year: 2011

The original definition of quantum discord of bipartite states was defined over projective measurements; in this paper we discuss some generalizations of it. These generalizations are defined over general measurements, rank-1 general measurements or Neumark extension measurements. We investigate the non-negativity, zero-discord sets of all these quantum discords and some properties of them. © 2011 IOP Publishing Ltd.

Minato F.,Japan Atomic Energy Agency | Bai C.L.,Sichuan University
Physical Review Letters | Year: 2013

The effect of the tensor force on β decay is studied in the framework of the proton-neutron random phase approximation with the Skyrme force. The investigation is performed for even-even semimagic and magic nuclei, Si34, Ni68,78, and Sn132. The tensor correlation induces strong impact on the low-lying Gamow-Teller state. In particular, it improves the β-decay half-lives. Q and ft values are also investigated and compared with experimental data. © 2013 American Physical Society.

Polyakov D.,Sichuan University | Polyakov D.,Institute for Information Transmission Problems IITP
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

We investigate the special case of quintic interactions for massless higher spin gauge fields using the string-theoretic vertex operator construction for higher spin gauge fields in Vasiliev's framelike formalism. We compute explicitly the related five-point interaction vertex in the low energy limit of string theory and find that the structure of the quintic s1-s2-s3-s4-s5 higher spin interaction gets drastically simplified and localized if (a) the spin values satisfy the constraint s1+s2+s3=s4+s5+2 (and, more generally, if the sum of three spin values roughly equals the sum of the remaining two) and (b) one of the spin values s4 or s5 is sufficiently small. In this paper, the explicit computation is done for the case s4=4. © 2016 American Physical Society.

Chen X.,University of Sichuan | Wan Y.,University of Sichuan | Zhou T.,University of Sichuan | Li J.,Sichuan University | Wei Y.,University of Sichuan
Immunotherapy | Year: 2013

Aim: To assess whether ursolic acid (UA) can attenuate lipopolysachharide (LPS)-induced acute lung injury and improve the survival time in a mouse model. Materials & methods: The mice were challenged with LPS and survival time was monitored from 0-96 h after LPS treatment. TNF-α, IL-6, IL-1, HMGB1, nitric oxide (NO) and IL-10 concentration in serum were measured by ELISA. Myeloperoxidase activity, malondialdehyde, lung wet:dry weight ratio and lung permeability in lung tissues were detected. NF-B, HMGB1 and inducible NO synthase in the lungs were detected by western blot. Results: UA markedly rescued lethality, improved survival time and lung pathological changes, inhibited TNF-α, IL-6, IL-1, HMGB1 and NO, and increased IL-10 expression. In addition, UA can also decrease myeloperoxidase, malondialdehyde, lung wet:dry weight ratio and lung permeability. UA attenuated NF-B, HMGB1 and inducible NO synthase protein expression in the lungs. Conclusion: The results suggest that UA is capable of improving survival time and LPS-induced acute lung injury. UA has a potentially therapeutic role in septic shock. © 2013 Future Medicine Ltd.

Li C.Y.,Beijing University of Chemical Technology | Yuan W.,Chinese Academy of Sciences | Jiang H.,Beijing University of Chemical Technology | Li J.S.,Sichuan University | And 3 more authors.
Bioconjugate Chemistry | Year: 2011

Successful gene transfection on a tissue scaffold is of crucial importance in facilitating tissue repair and regeneration by enabling the localized production of therapeutic drugs. Polycaprolactone (PCL) has been widely adopted as a scaffold biomaterial, but its unfavorable cell-adhesion property needs to be improved. In this work, the PCL film surface was conjugated with poly((2-dimethyl amino)ethyl methacrylate) (P(DMAEMA))/gelatin complexes via surface-initiated atom transfer radical polymerization (ATRP) for improving cell immobilization and subsequent gene transfection. A simple aminolysis-based method was first used for the covalent immobilization of ATRP initiators on the PCL film. Well-defined P(DMAEMA) brushes were subsequently prepared via surface-initiated ATRP from the initiator-functionalized PCL surfaces. The P(DMAEMA) chains with a pK a of 7.0-7.3 were used for conjugating gelatin with a pI of 4.7 via electrostatic interaction. The amount of complexed gelatin increased as that of the grafted P(DMAEMA) layer. The cell-adhesion property on the functionalized PCL surface could be controlled by adjusting the ratio of P(DMAEMA)/gelatin. It was found that the gene transfection property on the immobilized cells was dependent on the density of the immobilized cells on the functionalized PCL film. With the good cell-adhesive nature of gelatin and the efficient gene transfection on the dense immobilized cells, the incorporating the suitable of P(DMAEMA)/gelatin complexes onto PCL surfaces could endow the PCL substrates new and interesting properties for potential tissue engineering applications. © 2011 American Chemical Society.

Xu H.-Y.,Harbin University of Science and Technology | Zheng Z.,Sichuan University | Mao G.-J.,Heilongjiang University
Journal of Hazardous Materials | Year: 2010

The existence of 'electrostatic poles' on the schorl surface encouraged us to apply schorl for a TiO2 support. TiO2/schorl composite photocatalyst was prepared and characterized by XRD, SEM and UV/DRS, and their photocatalytic activity was evaluated by discoloration of acid fuchsine (AF). The results indicated that TiO2 existed in the form of anatase and was well deposited and enwrapped on the schorl surface. The absorption edge of TiO2/schorl exhibited a slight red shift in the UV/DRS spectra, compared with that of pure TiO2. The photocatalytic activity of TiO2/schorl for AF discoloration was higher than that of pure TiO2. The AF discoloration ratio approached 100% after irradiation time of 12 h. The optimum photocatalyst was found to be that containing 4.76 wt.% of schorl and sintered at 550 °C. The reaction followed pseudo-first-order kinetics, discussed by the Langmuir-Hinshelwood model. Hypotheses were proposed to interpret the mechanism for the enhanced photocatalytic activity of TiO2/schorl. © 2009 Elsevier B.V. All rights reserved.

Li Y.,Gannan Normal University | Liu C.,Gannan Normal University | Xie Y.,Gannan Normal University | Li X.,Gannan Normal University | And 3 more authors.
Chemical Communications | Year: 2013

The K+-induced switching of valinomycin has been studied using a molecular template formed by an aromatic oligoamide macrocycle at the liquid/solid interface by scanning tunneling microscopy (STM). Individual valinomycin and its K+ complex can be identified and resolved in the molecular template, and the high-resolution STM images of valinomycin and its K+ complex show triangle-like and cyclic structural characteristics, respectively. © 2013 The Royal Society of Chemistry.

RADA16-I peptide hydrogel, a type of nanofiber scaffold derived from self-assembling peptide RADA16-I, has been extensively applied to regenerative medicine and tissue repair in order to develop novel nanomedicine systems. In this study, using RADA16-I peptide hydrogel, a three-dimensional (3D) cell culture model was fabricated for in vitro culture of three ovarian cancer cell lines. Firstly, the peptide nanofiber scaffold was evaluated by transmission electron microscopy and atom force microscopy. Using phase contrast microscopy, the appearance of the representative ovarian cancer cells encapsulated in RADA16-I peptide hydrogel on days 1, 3, and 7 in 24-well Petri dishes was illustrated. The cancer cell-nanofiber scaffold construct was cultured for 5 days, and the ovarian cancer cells had actively proliferative potential. The precultured ovarian cancer cells exhibited nearly similar adhesion properties and invasion potentials in vitro between RADA16-I peptide nanofiber and type I collagen, which suggested that RADA16-I peptide hydrogel had some similar characteristics to type I collagen. The precultured ovarian cancer cells had two-fold to five-fold higher anticancer drug resistance than the conventional two-dimensional Petri dish culture. So the 3D cell model on peptide nanofiber scaffold is an optimal type of cell pattern for anticancer drug screening and tumor biology.

Fu Z.-W.,Sichuan University
Chinese Physics C | Year: 2014

Within mixed-action chiral perturbation theory (MAχPT), Sasa's derivation of the bubble contribution to scalar a0 meson is extended to those of scalar κ and σ mesons. We revealed that the κ bubble has two double poles and the σ bubble contains a quadratic-in-t2 growth factor stemming from the multiplication of two double poles for a general mass tuning of valence quarks and sea quarks. The corresponding preliminary analytical expressions in MAχPT with 2+1 chiral valence quarks and 2+1 staggered sea quarks will be helpful for lattice studies of scalar mesons. © 2014 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Yao K.,Nanchang University | Xu Y.-X.,Sichuan University | Li F.,Nanchang University | Wang X.,Nanchang University | Zhou L.,Nanchang University
Advanced Optical Materials | Year: 2015

A ternary blend approach to enhance light harvesting is reported by utilizing ladder-type donor polymers with complementary absorption in polymer solar cells. The broader absorption range can be universally achieved by blending individual ladder-type polymers without changes to their electronic properties and morphologies with boosted photocurrent in photovoltaic devices. This method presents a universal and efficient way to absorb wide-spectrum light by using simple processing conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang S.,Sichuan University | Tian G.Y.,United Technologies | Wilson J.,Newcastle University
Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME | Year: 2011

Thermography has proven to be one of the most effective approaches to detect cracks in conductive specimens over a relatively large area. Pulsed eddy current stimulated thermography is an emerging integrative nondestructive approach for the detection and characterization of surface and subsurface cracks. In this paper, heating behaviors of edge cracks, excited by pulsed eddy currents, are examined using numerical simulations. The simulations are performed using COMSOL multiphysics finite element method simulation software using the AC/DC module. The simulation results show that in the early heating stage, the temperature increases more quickly at the crack tip compared with other points on the sample. The results indicate that to maximize sensitivity, the response should be analyzed in the early stages of the heating period, no more than 100 ms for samples in which we are interested. The eddy current density distribution is changed with a variation in inductor orientation, but the crack tips remain the "hottest" points during the excitation period, which can be used for robust quantitative defect evaluation. Signal feature selection, transient temperature profile of the sample, and influence of the inductor orientation on the detection sensitivity for edge cracks are investigated. The work shows that positioning of the inductor, perpendicular to the crack line, results in the highest sensitivity for defect detection and characterization. The crack orientation can be estimated through the rotation of the linear inductor near the sample edge and the crack tips. Copyright © 2011 by ASME.

Perez D.,Los Alamos National Laboratory | Luo S.-N.,Los Alamos National Laboratory | Luo S.-N.,Sichuan University | Voter A.F.,Los Alamos National Laboratory | Germann T.C.,Los Alamos National Laboratory
Physical Review Letters | Year: 2013

While preexisting defects are known to act as nucleation sites for plastic deformation in shocked materials, the kinetics of the early stages of plastic yield are still poorly understood. We use atomistic simulation techniques to investigate the kinetics of plastic yield around small preexisting voids in copper single crystals under uniaxial tensile strain. We demonstrate that at finite temperatures, these voids are stabilized by strong entropic effects that confer them significant lifetimes even when the static mechanical instability limit is exceeded. By virtue of its entropic nature, this effect is shown to be proportionally stronger at higher temperatures. Even accounting for thermal activation, very small voids prove to be extremely inefficient nucleation sites for plasticity. © 2013 American Physical Society.

Meng Z.,Sichuan University
Lin chuang er bi yan hou tou jing wai ke za zhi = Journal of clinical otorhinolaryngology, head, and neck surgery | Year: 2012

To study the long-term rehabilitation effects for treating tinnitus by tinnitus masking combined with counseling. Complete the tinnitus handicap inventory(THI) for participants before treatment and after six months, 1 year, 2 years, 3 years. Eighty-six tinnitus patients participated. Nine participants and sixteen, twenty-six, sixteen participants drop-up during the follow up after half-year, 1 year, 2 years, 3 years separately. The percentage of participants whose THI score decreased more than or equal to 20 are 66%, 56%, 40%, 48% after half year, 1 year, 2 years, 3 years respectively. The tinnitus related handicap improved by tinnitus masking combined with counseling after 1 year. The drop-out rate was increase after follow-up 1 year. The long-term rehabilitation effects for tinnitus treatment is still needed.

Qin Y.,Chongqing University | Qin Y.,Sichuan University | Mao Y.,Chongqing University | Tang B.,Chongqing University
Journal of Sound and Vibration | Year: 2013

Using different transform basis, the vibration signal components, such as impulses, harmonics and modulated components, can be effectively separated by basis pursuit. For multicomponent vibration signals, this paper proposes a new vibration signal component separation approach by iteratively using basis pursuit. The signal is firstly denoised by basis pursuit denoising and the impulsive component can be separated by using identity matrix and redundant Fourier basis. Then signal components with different frequency ranges can be separated by using short-time Fourier transform basis with different window lengths, and the components with high frequency are separated after each iteration. To choose the best basis from the dictionary, the separation coefficient is proposed for evaluating the separating performance of the transform basis. The proposed approach, empirical mode decomposition (EMD) and matching pursuit are respectively applied to analyzing a simulated faulty vibration and a simulated faulty gear vibration signal. The comparison results demonstrate its superiority to EMD and matching pursuit in separation accuracy. Finally, the proposed approach is used for detecting the faults of a rotor and rolling bearings. The results further show that this proposed method can be effectively applied to mechanical fault diagnosis. © 2013 Elsevier Ltd.

Twenty-one microsatellite loci were isolated from AC-enriched library of Tibetan macaque (Macaca thibetana). The number of alleles at the 21 microsatellite loci ranged from 8 to 15, with an average of 12.2 per locus. Polymorphism information content (PIC) ranged from 0.805 to 0.910 with an average of 0.873. The observed and expected heterozygosities ranged from 0.208 to 0.792 and from 0.843 to 0.938, respectively. These microsatellite loci will be useful for future studies that relate to the genetic diversity and population structure of Tibetan macaque.

Chen Z.-Q.,China West Normal University | Xue Y.,Sichuan University
Journal of Theoretical and Computational Chemistry | Year: 2013

Hydroxyl-radical-induced damage to cytosine leads to a multitude of base modifications, which contribute to the natural processes of aging, mutagenesis and carcinogenesis. The stable products resulting from the main hydroxyl-radical-induced cytosine hydroperoxide, 5-hydroxy-6-hydroperoxyl-5,6- dihydrocytosine (5-OH-6-OOH-DHC), have been mapped out in the present work for the first time using ab initio calculations. Optimized geometries of all stationary structures in the gas phase were determined at the MP2 and B3LYP using the 6-31G(d) basis set and at the B3LYP/6-311++G(d,p) levels of theory. Energies were also determined at the G3MP2 level of theory. Meanwhile, full optimization of all stationary points were also performed in aqueous solution at the B3LYP/CPCM/6-31G(d) level of theory to evaluate the solvent effect. Three distinct possible pathways, pathways A-C, were evaluated. For pathway C, four channels, channels D-G, were characterized in turn. In each pathway, both the direct and the water-mediated processes were considered. The calculated results clearly manifest that (i) pathway C is kinetically favored over pathways A and B and is the most energetically feasible decomposition process of 5-OH-6-OOH-DHC; (ii) for pathway C, channels D, E and G are energetically feasible mechanisms and 6,7-dihydroxy-[1,3,5]triazepane-2,4-dione, 1-carbamoyl-2-oxo-4,5- dihydroxyimidazolidine, and biuret therefore are predicted to be the kinetically favored decomposition products of 5-OH-6-OOH-DHC; (iii) channel G may be kinetically favored over channels D and E and have the highest possibility to occur; (iv) the thermal decomposition of 5-OH-6-OOH-DHC can be significantly promoted by the presence of one explicit water molecule. Apart from characterizing the experimental products well, the main striking result of the present DFT computational study is the identification of a new theoretical optimum decomposition product, i.e. 6,7-dihydroxy-[1,3,5]triazepane-2,4-dione. The data and insights presented here have elucidated the chemical properties of 5-OH-6-OOH-DHC in free radical reactions and should facilitate to assess their mutagenic features. © 2013 World Scientific Publishing Company.

Huang C.M.,Sichuan University | Retallack G.J.,University of Oregon | Wang C.S.,China University of Geosciences
Cretaceous Research | Year: 2012

Pedogenic carbonates were collected from Early Cretaceous strata in Sichuan and Liaoning, China. These paleosol carbonates and calcareous paleosols were evaluated in order to reconstruct atmospheric CO 2 concentrations during the Early Cretaceous using a paleosol barometer. Using the isotopic ratios of pedogenic carbonates from Early Cretaceous (early-middle Berriasian, early Valanginian) strata in Sichuan Basin, averaged atmospheric pCO 2 is estimated to have been 360 ppmv in the early-middle Berriasian and a mean value of 241 ppmv in the early Valanginian. In the late Barremian in western Liaoning, however the average was 530 ppmv, with a range of 365 ppmv and 644 ppmv, lower than previous estimates of pCO 2 for these time periods, consistent with the suggestion of overall climate cooling and paleotemperature fluctuation during the Early Cretaceous. This indicates that not all of the Cretaceous was a high or continuous CO 2 greenhouse, especially during Early Cretaceous. © 2011 Elsevier Ltd.

Zhang C.,University of Electronic Science and Technology of China | Yi Z.,Sichuan University
Neurocomputing | Year: 2010

Self-nonself discrimination has long been the fundamental model of modern theoretical immunology. Based on this principle, some effective and efficient artificial immune algorithms have been proposed and applied to a wide range of engineering applications. Over the last few years, a new model called "danger theory" has been developed to challenge the classical self-nonself model. In this paper, a novel immune algorithm inspired by danger theory is proposed for solving on-line supervised two-class classification problems. The general framework of the proposed algorithm is described, and several essential issues related to the learning process are also discussed. Experiments based on both artificial data sets and real-world problems are carried out to visualize the learning process, as well as to evaluate the classification performance of our method. It is shown empirically by the experimental results that the proposed algorithm exhibits competitive classification accuracy and generalization capability. © 2010 Elsevier B.V. All rights reserved.

Jiang H.,Beijing University of Chemical Technology | Wang X.B.,Nanjing Normal University | Li C.Y.,Beijing University of Chemical Technology | Li J.S.,Sichuan University | And 4 more authors.
Langmuir | Year: 2011

Polycaprolactone (PCL) has been widely adopted as a scaffold biomaterial, but further improvement of the hemocompatibility of a PCL film surface is still needed for wide biomedical applications. In this work, the PCL film surface was functionalized with zwitterionic poly(3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate) (P(DMAPS)) brushes via surface-initiated atom transfer radical polymerization (ATRP) for enhancing hemocompatibility. Kinetics study revealed an approximately linear increase in graft yield of the functional P(DMAPS) brushes with polymerization time. The blood compatibilities of the modified PCL film surfaces were studied by platelet adhesion tests of platelet-rich plasma and human whole blood, hemolysis assay, and plasma recalcification time (PRT) assay. The improvement of hemocompatibility is dependent on the coverage of the grafted P(DMAPS) brushes on the PCL film. Lower or no platelet and blood cell adhesion was observed on the P(DMAPS)-grafted film surfaces. The P(DMAPS) grafting can further decrease hemolysis and enhance the PRT of the PCL surface. With the versatility of surface-initiated ATRP and the excellent hemocompatibility of zwitterionic polymer brushes, PCL films with desirable blood properties can be readily tailored to cater to various biomedical applications. © 2011 American Chemical Society.

Zeng W.-C.,University of Sichuan | Zhang Z.,Sichuan University | Jia L.-R.,University of Sichuan
Carbohydrate Polymers | Year: 2014

A novel antioxidant polysaccharide (APC) was isolated and characterized from pine needles of Cedrus deodara with the evaluation of its in vitro antioxidant activity. According to gel filtration chromatography, high performance size exclusion chromatography, gas chromatography-mass spectrometry, partial acid hydrolysis, periodic acid oxidation, Smith degradation and methylation analysis, APC was observed to be an acidic heteropolysaccharide (composed of glucose, arabinose, mannose and xylose in a molar ratio of 45.84:1:2.35:1.73) with the molecular weight of 1.53 × 104 Da, and the backbone was mainly composed by glucose, mannose and xylose in the form of (1 → 4) linked. Meanwhile, APC exhibited the remarkable antioxidant activity to scavenge free radicals and inhibit the oxidative injury of DNA and cells. The present results suggested that APC could be a potential antioxidant agent for preparing functional foods and nutraceuticals applied in food and pharmaceutical industries. © 2014 Published by Elsevier Ltd.

Su Y.,University of Sichuan | Xie Y.,University of Sichuan | Hou X.,University of Sichuan | Lv Y.,Sichuan University
Applied Spectroscopy Reviews | Year: 2013

In recent years, many nanomaterials-assisted chemiluminescence (CL) systems have been developed to improve the sensitivity and to expand the scope of their analytical applications. In these new systems, nanomaterials participate in CL reactions as catalysts, labels, reductants, luminophors, or energy acceptors. This review mainly focuses on the recent analytical applications of metal nanoparticles, magnetic nanoparticles, quantum dots (QDs), and carbon-based nanomaterials (carbon nanotubes and graphene) in liquid-phase CL systems. Recent advances in electrochemiluminescence based on nanotechnology and its analytical applications, especially in immunoassay, DNA analysis, and other biological analyses, are also summarized. Finally, we discuss some critical challenges in this field and speculate about their solutions. A total of 177 references mainly in the last 5 years are included in this review. © 2014 Copyright Taylor and Francis Group, LLC.

OBJECTIVES: The early detection of suspiciously recurrent breast cancer is of significant importance. The aim of the present meta-analysis was to evaluate the overall diagnostic accuracy of fluorine-18 fluorodeoxyglucose (F-FDG)-PET or PET/computed tomography (CT) for the detection of relapse in suspected recurrent breast cancer. MATERIALS AND METHODS: Medline, Embase, Web of Science, and Cochrane databases were searched for articles on suspiciously recurrent breast cancer and F-FDG-PET or PET/CT up to 10 January 2016. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve (AUC) were calculated. A meta-regression analysis was carried out to explore potential sources of heterogeneity. RESULTS: A total of 26 studies with 1752 patients with suspiciously recurrent breast cancer were included for the analysis; among these, 56.8% because of elevation of tumor markers, in 33.9%, there was suspicion on conventional imaging modalities, and in 9.4%, suggestive clinical symptoms or physical examinations were found. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of F-FDG-PET or PET/CT were 0.90 [95% confidence interval (CI), 0.88–0.90], 0.81 (95% CI, 0.78–0.84), 4.64 (95% CI, 3.50–6.14), 0.12 (95% CI, 0.08–0.16), and 46.52 (95% CI, 29.44-73.51), respectively. In addition, the overall AUC of F-FDG-PET or PET/CT was 0.9358. Meta-regression analysis showed that type of imaging modality (PET over PET/CT) might be a potential source of heterogeneity (P=0.0799). Furthermore, a subgroup analysis indicated that PET/CT appeared to harbor more specificity in the diagnosis of recurrent breast cancer (0.823 vs. 0.796, P=0.035). The increased AUC suggested increased accuracy of PET/CT over PET (0.9477 vs. 0.9111). CONCLUSION: F-FDG-PET, and in particular F-FDG-PET/CT, seemed to be a more valuable supplement to current surveillance techniques to detect relapse in suspected recurrent breast cancer patients. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Xiang Y.,Deakin University | Peng D.,Deakin University | Peng D.,Sichuan University | Natgunanathan I.,Deakin University | Zhou W.,Deakin University
IEEE Transactions on Multimedia | Year: 2011

This paper proposes an effective pseudonoise (PN) sequence and the corresponding decoding function for time-spread echo-based audio watermarking. Different from the traditional PN sequence used in time-spread echo hiding, the proposed PN sequence has two features. Firstly, the echo kernel resulting from the new PN sequence has frequency characteristics with smaller magnitudes in perceptually significant region. This leads to higher perceptual quality. Secondly, the correlation function of the new PN sequence has three times more large peaks than that of the existing PN sequence. Based on this feature, we propose a new decoding function to improve the robustness of time-spread echo-based audio watermarking. The effectiveness of the proposed PN sequence and decoding function is illustrated by theoretical analysis, simulation examples, and listening test. © 2010 IEEE.

Epigenetic regulation participates broadly in many fundamentally cellular and physiological processes. In this study, we found that DDB1, a protein originally identified as a factor involved in DNA repairing, plays important roles in regulating organ size, growth habit and photosynthesis in tomato via an epigenetic manner. We generated transgenic tomato plants overexpressing an alternatively spliced DDB1 transcript (DDB1(F) , prevalently present in tomato tissues) and found the primary transformants displayed small-fruited "cherry tomato" in companion with strikingly enhanced shoot branching and biomass, dark-green leaves with elevated chlorophyll accumulation, and increased soluble solids in fruits. Significantly, these phenotypic alterations did not segregate with the DDB1(F) transgene in subsequent generations, suggesting that the effect of DDB1(F) on multiple agronomic traits is implemented via an epigenetic manner and is inheritable over generations. We speculate that DDB1, as a core subunit in the recently identified CUL4-based E3 ligase complex, mediates the 26S proteasome-dependent degradation of a large number of proteins, some of which might be required for perpetuating epigenetic marks on chromatins.

Huang C.,Sichuan University | Retallack G.J.,University of Oregon | Wang C.,China University of Geosciences | Huang Q.,Petrochina
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

A dramatic change in atmospheric composition has been postulated because of global carbon cycle disruption during the Cretaceous (K)-Tertiary (T) transition following the Chicxulub impact and Deccan Trap eruptions. Here, pedogenic carbonates were collected from drill core of a borehole (SK-1 (N)) straddling the Late Cretaceous and early Paleocene strata in the Songliao Basin, northeast China, to reconstruct atmospheric CO2 concentrations using a paleosol paleobarometer. Our estimates for atmospheric pCO2 from paleosol carbonates range between 277±115ppmv and 837±164ppmv between 67.8Ma and 63.1Ma. One large (~66-65.5Ma) and several small CO2 spikes (~64.7-~64.2Ma) during the latest Maastrichtian to earliest Danian are reported here and incorporated with previously published pCO2 estimates also estimated from paleosol carbonates. These CO2 spikes are attributed to one-million-year-long emplacement of the large Deccan flood basalts along with the extraterrestrial impact at the K-T boundary. © 2013 Elsevier B.V.

Yi Z.,Sichuan University
IEEE Transactions on Neural Networks | Year: 2010

The competitive layer model (CLM) can be described by an optimization problem. The problem can be further formulated by an energy function, called the CLM energy function, in the subspace of nonnegative orthant. The set of minimum points of the CLM energy function forms the set of solutions of the CLM problem. Solving the CLM problem means to find out such solutions. Recurrent neural networks (RNNs) can be used to implement the CLM to solve the CLM problem. The key point is to make the set of minimum points of the CLM energy function just correspond to the set of stable attractors of the recurrent neural networks. This paper proposes to use LotkaVolterra RNNs (LV RNNs) to implement the CLM. The contribution of this paper is to establish foundations of implementing the CLM by LV RNNs. The contribution mainly contains three parts. The first part is on the CLM energy function. Necessary and sufficient conditions for minimum points of the CLM energy function are established by detailed study. The second part is on the convergence of the proposed model of the LV RNNs. It is proven that interesting trajectories are convergent. The third part is the most important. It proves that the set of stable attractors of the proposed LV RNN just equals the set of minimum points of the CLM energy function in the nonnegative orthant. Thus, the LV RNNs can be used to solve the problem of the CLM. It is believed that by establishing such basic rigorous theories, more and interesting applications of the CLM can be found. © 2010 IEEE.

Zhang H.,Sichuan University | Miyamoto Y.,Nanosystem Research Institute | Rubio A.,University of the Basque Country
Physical Review Letters | Year: 2012

Helium ion microscopy (HIM), which was released in 2006 by Ward et al., provides nondestructive imaging of nanoscale objects with higher contrast than scanning electron microscopy. HIM measurement of suspended graphene under typical conditions is simulated by first-principles time-dependent density functional theory and the 30 keV He+ collision is found to induce the emission of electrons dependent on the impact point. This finding suggests the possibility of obtaining a highly accurate image of the honeycomb pattern of suspended graphene by HIM. Comparison with a simulation of He0 under the same kinetic energy shows that electron emission is governed by the impact ionization instead of Auger process initiated by neutralization of He+. © 2012 American Physical Society.

Huang L.,CNRS Laboratory of Chemistry and Reactivity of Solids | Huang L.,Sichuan University | Aymard L.,CNRS Laboratory of Chemistry and Reactivity of Solids | Bonnet J.-P.,CNRS Laboratory of Chemistry and Reactivity of Solids
Journal of Materials Chemistry A | Year: 2015

A 0.7MgH2 + 0.3TiH2 mixture was prepared by reactive grinding of Mg and Ti powders under hydrogen and tested as a conversion electrode for lithium-ion batteries. This composite presents superior electrochemical properties compared to MgH2 or TiH2 based electrodes, either in terms of reversible capacities or polarization versus applied current rate. A substantial reversible capacity of 1540 mA h g-1 is measured at a suitable potential of 0.52 V vs. Li+/Li0 (current rate 0.1Li h-1). For the same current rate, electrode polarization is limited to 0.2 V and stabilizes at 0.46 V for 1.0Li h-1 while a continuous polarization increase is observed for MgH2 based electrodes. In situ XRD analyses of this composite demonstrate that Mg and Ti hydrides are both electrochemically active and contribute together to the capacity. TiH2 improves MgH2 conversion process kinetics while MgH2 enables a reversible conversion reaction for TiH2. The three consecutive reactions are: (1) MgH2 + 2Li+ + 2e- ⇌ Mg + 2LiH; (2) δ-TiH2 + xLi+ + xe- ⇌ δ-TiH2-x + xLiH (x ≤ 0.5) and (3) δ-TiH2-x + (2 - x)Li+ + (2 - x)e- ⇌ α-Ti + (2 - x)LiH (x = 0.5). This is, to our knowledge, the first example of a reversible lithium conversion process with TiH2 powder. © The Royal Society of Chemistry 2015.

Fu Z.-W.,Sichuan University
Chinese Physics Letters | Year: 2011

We study the σ meson in 2+1 flavor full quantum chromodynamics (QCD) with sufficiently light u and d quarks. The point-to-point correlator is measured for the σ channel in the "Asqtad" improved staggered fermion formulation. Particular attention is paid to its disconnected diagram and bubble contribution. After chiral extrapolation, we obtain the σ mass with 70653 MeV, which is close to the observed σ meson within error, and is heavier than the ππ threshold. The simulations are carried out with MILC 2+1 flavor gauge configurations at lattice spacing of a 0.15 fm. © 2011 Chinese Physical Society and IOP Publishing Ltd.

Mu D.,Chengdu University of Technology | Shen B.-L.,Sichuan University
Surface and Coatings Technology | Year: 2013

In this study, boronizing of 99.95% pure cobalt was performed in a solid medium by using Commercial LSB-II powders (that contain SiC) at 850, 900 and 950°C for 2, 4, 6 and 8h, respectively. The surface modified samples were examined by means of scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS), X-ray diffraction, microhardness tester and ring-on-block wear tester. Samples boronized had Co2B phase or Co2B plus Co2Si phases depending on the process temperatures. The depth of modified layer ranged from 40 to 186μm, depending on treatment temperature and time. The hardness of boride layer is much higher than that of silicide layer and substrate, and the wear resistance of the boride layer is more excellent than that of the silicide layer. © 2013 Elsevier B.V.

Wang S.,Sichuan University
Journal of Software Engineering | Year: 2012

This research studies the key problem of multi-attribute allocation in multi-attribute decision. Proper attribute allocation is very important in the decision process. In order to solve uncertainty from distribution of attributes, a novel multi-attribute allocation method is presented based on optimization theory and maximum entropy principle. A linear combination weights mathematical model is also proposed through mathematical derivation. Numerical results are provided using typical test data and prove the efficiency of the novel method. © 2012 Academic Journals Inc.

Resource scheduling based on SLA(Service Level Agreement) in cloud computing is NP-hard problem. There is no efficient method to solve it. This paper proposes an optimal model for the problem and give an algorithm by applying stochastic integer programming technique. Applying Gr̈obner bases theory for solving the stochastic integer programming problem and the experimental results of the implementation are also presented. © 2012 ACADEMY PUBLISHER.

Zhang S.,Beihang University | Xing Y.,Beihang University | Jiang T.,Beihang University | Du Z.,Beihang University | And 3 more authors.
Journal of Power Sources | Year: 2011

Nanoporous copper (NPC), as a new kind of porous metal prepared by dealloying, is introduced into the lithium-ion battery as both the current collector and substrate of active material. The nanoporous copper has three-dimensional structure composed of large channels (hundreds of nanometers) and small pores (tens of nanometers) on the channel walls. Anodes were prepared by electroless depositing of a thin layer of tin on NPC and copper foil. By comparing the electrochemical performance of both electrodes, the nanostructured electrode exhibits much higher areal capacity and better Coulombic efficiency than planar electrode. © 2010 Elsevier B.V. All rights reserved.

Wang W.,University of Sichuan | Zhang M.-J.,University of Sichuan | Xie R.,University of Sichuan | Ju X.-J.,University of Sichuan | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2013

Hole in one! Hole-shell microparticles (blue, see picture) with controllable structures and flexible internal surfaces have been fabricated from W/O/W emulsions. These microparticles could be used as microcontainers for the controlled capture/release of molecules, microsphere classification/separation, confined cell culture, or as microreactors for catalysis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zheng H.,National Institute of Nuclear Physics, Italy | Zhu L.,Sichuan University
Advances in High Energy Physics | Year: 2016

We compare two types of Tsallis distribution, that is, with and without thermodynamical description, using the experimental data from the STAR, PHENIX, ALICE, and CMS Collaborations on the rapidity and energy dependence of the transverse momentum spectra in p + p collisions. Both of them can fit the particle spectra well. We show that the Tsallis distribution with thermodynamical description gives lower temperatures than the ones without it. The extra factor m T (transverse mass) in the Tsallis distribution with thermodynamical description plays an important role in the discrepancies between the two types of Tsallis distribution. But for the heavy particles, the choice to use m T or E T (transverse energy) in the Tsallis distribution becomes more crucial. © 2016 H. Zheng and Lilin Zhu.

Here we have realized three goals in a new potassium-sodium niobate material using CuO as sintering aid, such as low temperature sintering, the suppression in the loss of alkali metals, and attaining a high d33. Low-temperature sintered 0.96(K0.46Na0.54)Nb0.95Sb0.05O3-0.04Bi0.5(Na0.82K0.18)0.5ZrO3 ceramics were made conducting by adding CuO using an ordinary ceramic fabrication technique. The sintering temperatures drop from 1095 °C to 950°C when the CuO content is increased from 0 to 2.5 wt%, and the K and Na loss could be also prevented under a low processing temperature. In addition, the ceramics undergo a phase transition with increasing CuO content, such as from a rhombohedral-tetragonal phase coexistence to the mixture of both rhombohedral-orthorhombic and orthorhombic-tetragonal phase boundaries. The inhomogeneous Cu2+ distributions become more obvious as the CuO content rises, i.e., the excess Cu2+ aggregates at the small grains region for a low CuO content (x ≤ 1.5), and at the small and large grains zones for x = 2.5. The dielectric constant gradually decreases as the CuO increases, and the dielectric loss is lowered by adding CuO content. A well polarization vs. electric field (P-E) loop is seen in the ceramics with x ≤ 2.5, and those with x = 2.5 possess a high d33 of 310 pC N-1 even if the sintering temperatures drop down to 950°C. As a result, it is an efficient way to promote the piezoelectricity of copper oxide-modified alkaline niobate ceramics using a low-temperature sintering technique. This journal is © the Partner Organisations 2014.

Hsieh I.-F.,University of Akron | Sun H.-J.,University of Akron | Fu Q.,Sichuan University | Lotz B.,Charles Sadron Institute | And 2 more authors.
Soft Matter | Year: 2012

The solvent-induced spherical structure in a polystyrene-block- polydimethylsiloxane (PS-b-PDMS) block copolymer was obtained and stabilized by preparing both the bulk and thin films from propylene glycol methyl ether acetate (PGMEA) solutions. The diblock copolymer possessed a total molecular weight of 42 kDa with a PS volume fraction of 72.2%, and it formed a cylindrical phase structure in the equilibrium bulk state. During thermal annealing, only changes in the sphere size and packing rearrangement were found. In contrast, a unique structure evolution route was observed during solvent treatments. Under a controlled vapour of a PS selective solvent, an oscillation of the structural transition between spheres and cylinders was observed in the thin films. The kinetics of this oscillation of structural transition was found to be closely related to the solvent vapour concentration and film thickness. This experiment revealed a unique ordering pathway towards the equilibrium structure in the thin film for this strongly segregated PS-b-PDMS diblock copolymer. This journal is © The Royal Society of Chemistry 2012.

Huang X.,University of Sichuan | Liao X.,University of Sichuan | Shi B.,Sichuan University
Journal of Hazardous Materials | Year: 2010

This study describes a new approach for the preparation of tannin-immobilized adsorbent by using mesoporous silica bead as the supporting matrix. Bayberry tannin-immobilized mesoporous silica bead (BT-SiO2) was characterized by powder X-ray diffraction to verify the crystallinity, field-emission scanning electron microscopy to observe the surface morphology, and surface area and porosity analyzer to measure the mesoporous porous structure. Subsequently, the adsorption experiments to Cr(III) were applied to evaluate the adsorption performances of BT-SiO2. It was found that the adsorption of Cr(III) onto BT-SiO2 was pH-dependent, and the maximum adsorption capacity was obtained in the pH range of 5.0-5.5. The adsorption capacity was 1.30 mmol g-1 at 303 K and pH 5.5 when the initial concentration of Cr(III) was 2.0 mmol L-1. Based on proton nuclear magnetic resonance (HNMR) analyses, the adsorption mechanism of Cr(III) on BT-SiO2 was proved to be a chelating interaction. The adsorption kinetic data can be well described using pseudo-first-order model and the equilibrium data can be well fitted by the Langmuir isothermal model. Importantly, no bayberry tannin was leached out during the adsorption process and BT-SiO2 can simultaneously remove coexisting metal ions from aqueous solutions. In conclusion, this study provides a new strategy for the preparation of tannin-immobilized adsorbents that are highly effective in removal of heavy metals from aqueous solutions. Crown Copyright © 2009.

Guo W.-Z.,CAS Institute of Theoretical Physics | Guo W.-Z.,University of Chinese Academy of Sciences | He S.,CAS Institute of Theoretical Physics | Tao J.,CAS Institute of Theoretical Physics | Tao J.,Sichuan University
Journal of High Energy Physics | Year: 2013

We investigate the entanglement temperature of a small scale subsystem in low excited states by using holographic method. Especially, we study the entanglement entropy and entanglement temperature in higher derivative gravities which are considered as low thermal excitation of pure AdS gravity. We find that the entanglement entropy are related to the central charges of CFT living on the boundary. The relation between the variance of entanglement entropy and energy of a small scale subsystem has been also obtained. Furthermore, the relation is consistent with the first law-like relation that is proposed by Phys. Rev. Lett. 110 (2013)091602. Finally, we derive the formula of the variance of entanglement entropy in general excited states in gravity background with the Fefferman-Graham coordinates and the entanglement temperature can be figured out in special case. © 2013 SISSA, Trieste, Italy.

Xu J.,Sichuan University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2012

The original definition of quantum discord of bipartite states was defined over one-sided projective measurements, it describes quantum correlations more extensively than entanglement. Dakic, Vedral, and Brukner [Phys. Rev. Lett. 105 (2010) 190502] introduced a geometric measure of quantum discord, Luo and Fu [Phys. Rev. A 82 (2010) 034302] simplified the variation expression of this geometric measure. In this Letter we introduce a geometric measure of quantum discord over two-sided projective measurements. A simplified expression and a lower bound of this two-sided geometric measure are derived and explicit expressions are obtained for some special cases. © 2011 Elsevier B.V. All rights reserved.

Wen X.,University of Sichuan | Wu J.,Sichuan University | Wang F.,University of Sichuan | Liu B.,University of Sichuan | And 2 more authors.
Free Radical Biology and Medicine | Year: 2013

Reactive oxygen species (ROS), chemically reactive molecules containing oxygen, can form as a natural byproduct of the normal metabolism of oxygen and also have their crucial roles in cell homeostasis. Of note, the major intracellular sources including mitochondria, endoplasmic reticulum (ER), peroxisomes and the NADPH oxidase (NOX) complex have been identified in cell membranes to produce ROS. Interestingly, autophagy, an evolutionarily conserved lysosomal degradation process in which a cell degrades long-lived proteins and damaged organelles, has recently been well-characterized to be regulated by different types of ROS. Accumulating evidence has demonstrated that ROS-modulated autophagy has numerous links to a number of pathological processes, including cancer, ageing, neurodegenerative diseases, type-II diabetes, cardiovascular diseases, muscular disorders, hepatic encephalopathy and immunity diseases. In this review, we focus on summarizing the molecular mechanisms of ROS-regulated autophagy and their relevance to diverse diseases, which would shed new light on more ROS modulators as potential therapeutic drugs for fighting human diseases. © 2013 Elsevier Inc.

Li L.,Sichuan University
Advances in Information Sciences and Service Sciences | Year: 2012

Those traditional clustering algorithm have been no longer fit for the abnormal short texts such as micro blog. Therefore, this paper puts forward a hybrid clustering algorithm using zoning search of genetic algorithm to quickly find out the largest condensation point. At first, after the sliding windows been put up according to the publishing time of micro-blogging information, the density points in each window are calculated. Then zoning search and global search come into operation for the largest condensation points. In the course, it is of importance to ensure the overlapping area of sliding window to be connected. The solution is to take the last density point obtained in the previous window as the initial point of current window. It is proved that the proposed method can not only avoid local optima, but also achieve faster convergence speed under the conditions of right fitness function, proper selection operator and crossover operator. Furthermore, the recall rate and the precise rate of the proposed method are more reasonable than that of C-means algorithm in a contrast experiment in the micro-blogging environment.

Yao J.,University of Sichuan | Yang M.,University of Sichuan | Duan Y.,University of Sichuan | Duan Y.,Sichuan University
Chemical Reviews | Year: 2014

The combination of fluorescence and nanomaterials has developed into an emerging research area: fluorescent nanoparticles. Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology and have attracted increasing interest for bioanalytical labeling applications in recent years. The emerging development and innovation of luminescent nanoparticles (NP) with unique optical properties, yet complicated surface chemistry, paves new roads for fluorescence imaging and sensing as well as for in vitro and in vivo labeling in cells, tissues, and organisms. The labeling procedure can be straightforward provided that suitable functional groups are available on the target analyte. However, it can be difficult to reach a low detection limit in fluorescence detection due to the limited extinction coefficients or quantum yields of traditional organic dyes and also low dye-to-reporter molecule labeling ratio.

Yang C.,Sichuan University | Inoue Y.,Osaka University
Chemical Society Reviews | Year: 2014

Supramolecular photochirogenesis is a rapidly growing interdisciplinary area of science at the boundary of photochemistry, asymmetric synthesis and supramolecular chemistry. The major advantage of supramolecular photochirogenesis over the conventional molecular one is entropic in origin, being achieved by preorganizing substrate(s) in the ground state and manipulating subsequent photochemical transformation by weak but non-transient interactions in chiral supramolecular media. The chirality transfer often becomes more efficient through the cooperative non-covalent interactions and the confinement by host in both ground and excited states. Thus, all of the ground- and excited-state events, including complexation stoichiometry and affinity, chiroptical properties, photophysical behaviour and photochemical reactivity, jointly play pivotal roles in supramolecular photochirogenesis. This may appear to cause complication but in reality expands the range of manipulable factors and available experimental/theoretical tools for elucidating the mechanism and controlling photochirogenic processes both thermodynamically and kinetically, from which some new concepts/methodologies unique to supramolecular photochemistry, such as non-sensitizing catalytic photochirogenesis and wavelength-controlled photochirogenesis, have already been developed. In this review, we will discuss the recent progress and future perspective of supramolecular photochirogenesis. This journal is © the Partner Organisations 2014.

Fu Z.-W.,Sichuan University
Chinese Physics C | Year: 2012

We study the κ meson in 2+1 flavor QCD with sufficiently light u/d quarks. Using numerical simulations, we measure the point-to-point κ correlators in the "Asqtad" improved staggered fermion formulation. We then analyze these correlators using rooted staggered chiral perturbation theory (rS χPT), with particular attention paid to bubble contribution. After chiral extrapolation, we obtain the physical κ mass with 828±97 MeV, which is within the recent experimental value of 800-900 MeV. These numerical simulations are carried out with MILC 2+1 flavor gauge configurations at a lattice spacing of a 0.12 fm. © 2012 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Fu Z.-W.,Sichuan University | Detar C.,University of Utah
Chinese Physics C | Year: 2011

We studied the κ light scalar meson in 2+1 flavor full QCD with sufficiently light u and d quarks. Via lattice simulation we measured the correlators for the κ channel in the "Asqtad" improved staggered fermion formulation. After chiral extrapolation we obtained the mass of the κ meson with 826 ± 119 MeV, which is within recent experimental values of 800-900 MeV. The simulations were carried out with the MILC 2+1 flavor gauge configurations at lattice spacing a≈0.15 fm. © 2011 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Fu Z.-W.,Sichuan University | Detar C.,University of Utah
Chinese Physics C | Year: 2011

With sufficiently light u and d quarks the isovector (a0) and isosinglet (f0) scalar meson propagators are dominated at large distances by two-meson states. In the staggered fermion formulation of lattice QCD, taste-symmetry breaking causes a proliferation of multihadron states that complicates the analysis of these channels. Of special interest is the bubble contribution, which makes a considerable contribution to these channels. Using numerical simulation we have measured the correlators for both a0 and f0 channels in the "Asqtad" improved staggered fermion formulation in a MILC fine (a = 0.09 fm) lattice ensemble. We analyze those correlators using rooted staggered chiral perturbation theory (rSχPT) and achieve chiral couplings that are well consistent with previous determinations. © 2011 Chinese Physical Society.

Zhao W.,KTH Royal Institute of Technology | Zhao W.,Sichuan University | Glavas L.,KTH Royal Institute of Technology | Odelius K.,KTH Royal Institute of Technology | And 2 more authors.
Chemistry of Materials | Year: 2014

A one-pot reaction to synthesize electrically conductive hemicellulose hydrogels (ECHHs) is developed via a facile and green approach in water and at ambient temperature. ECHHs were achieved by cross-linking O-acetyl- galactoglucomannan (AcGGM) with epichlorohydrin in the presence of conductive aniline pentamer (AP) and were confirmed by infrared spectroscopy (IR) and elemental analysis. All hydrogels had macro-porous structures, and the thermal stability of ECHHs was improved by the addition of AP. Hydrogel equilibrium swelling ratios (ESRs) varied from 13.7 to 11.4 and were regulated by cross-linker concentration. The ESRs can also be tuned from 9.6 to 6.0 by changing the AP content level from 10 to 40% (w/w) while simultaneously altering conductivity from 9.05 × 10-9 to 1.58 × 10-6 S/cm. ECHHs with controllable conductivity, tunable swelling behavior, and acceptable mechanical properties have great potential for biomedical applications, such as biosensors, electronic devices, and tissue engineering. © 2014 American Chemical Society.

The historical group decision making cases can be referred to for the new tasks with the techniques of cases based reasoning. But in the procedure of multiple criterion group decision making, all the evaluation data are inevitably given in two formats, among which one is the utility format and the other is the pair-wise comparison one. In order to acquire the uniform data for the multiple criterion group decision making cases based reasoning, the comparison data both of the unsolved alternatives to the historical ones by the demander and of the alternatives by every expert in historical multi-criterion group decision making events have to be transformed into utilities. An association rule based method is utilized to carry that point. The basic idea of this method is to gather collective preference information as much as possible. So it could make the results approach the truth according to the group decision theory. The corresponding utility transformation model is proved in detail that it meets the collective experts?preference theoretically. And it is pivotal in the multiple criterion group decision making cases based reasoning. © 2011 Binary Information Press December, 2011.

Li P.,Hebei University of Technology | Sun Y.,Hebei University of Technology | Wang Q.,University of Sichuan | Wang Q.,Sichuan University
Liquid Crystals | Year: 2013

A polymer-stabilised blue-phase liquid crystal display (PSBP-LCD) with double-side in-plane switching (DS-IPS) electrode structure is proposed. This structure shows the transflective characteristics because the bottom electrodes are made by aluminium material. For transflective displays, it exhibits a well-matched voltage-dependent transmission and reflection curves through designing the width and gap of the top electrodes. When a bias voltage is applied on the top electrodes, it exhibits as a good viewing angle controllable display. © 2013 Copyright Taylor and Francis Group, LLC.

Jiang H.-Y.,Chongqing Technology and Business University | Sun B.,Chongqing Technology and Business University | Zheng X.-X.,Chongqing Technology and Business University | Chen H.,Sichuan University
Applied Catalysis A: General | Year: 2012

The heterogeneous selective hydrogenation of trans-4-phenyl-3-butene-2-one to allylic alcohol, catalyzed by Ir/SiO 2 stabilized with phosphines and modified by cinchona alkaloids, was described herein. Under the optimized conditions, the chemoselectivity to α,β-unsaturated alcohol was more than 99% with enantioselectivity up to 46%. © 2012 Elsevier B.V. All rights reserved.

Fu Z.-W.,Sichuan University
Communications in Theoretical Physics | Year: 2014

We deliver the realistic ab initio lattice investigations of K scattering. In the Asqtad-improved staggered dynamical fermion formulation, we carefully measure K four-point function in the I = 0 channel by moving wall sources without gauge fixing, and clearly find an attractive interaction in this channel, which is in agreement with the theoretical predictions. An essential ingredient in our lattice calculation is to properly treat the disconnected diagram. Moreover, we explain the difficulties of these lattice calculations, and discuss the way to improve the statistics. Our lattice investigations are carried out with the MILC 2 + 1 gauge configuration at lattice spacing a ≈ 0.15 fm. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Sprick R.S.,University of Liverpool | Jiang J.-X.,University of Liverpool | Jiang J.-X.,Shaanxi Normal University | Bonillo B.,University of Liverpool | And 7 more authors.
Journal of the American Chemical Society | Year: 2015

Photocatalytic hydrogen production from water offers an abundant, clean fuel source, but it is challenging to produce photocatalysts that use the solar spectrum effectively. Many hydrogen-evolving photocatalysts are active in the ultraviolet range, but ultraviolet light accounts for only 3% of the energy available in the solar spectrum at ground level. Solid-state crystalline photocatalysts have light absorption profiles that are a discrete function of their crystalline phase and that are not always tunable. Here, we prepare a series of amorphous, microporous organic polymers with exquisite synthetic control over the optical gap in the range 1.94-2.95 eV. Specific monomer compositions give polymers that are robust and effective photocatalysts for the evolution of hydrogen from water in the presence of a sacrificial electron donor, without the apparent need for an added metal cocatalyst. Remarkably, unlike other organic systems, the best performing polymer is only photoactive under visible rather than ultraviolet irradiation. © 2015 American Chemical Society.

Guo F.,Sichuan University
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2010

Bone cement samples were made of tetracalcium phosphate (TTCP) and monocalcium phosphate monohydrate(MCPM) powder (Ca/P = 1.67) by using water and 5.24 mg/ml of self-made type I collagen sol as hardening liquid with the solid-liquid ratio of 3:1, their setting time and compressive strength were tested. The results showed that: the compressive strength of TTCP/MCPM bone cement containing collagen could increase from 17.8 +/- 1.9 MPa to 22.7 +/- 1.6 MPa, but its setting time hasn't been significantly affected; the compressive strength of both samples immersed in simulated body fluid (SBF) could increase, and the growth rate of the sample containing collagen increased especially; both samples immersed in SBF for 4d and 14d, whose compressive strength could increase to 31.8 +/- 3.9 MPa (collagen)/19.5 +/- 1.3 MPa and 38.1 +/- 3.1 MPa (collagen)/21.9 +/- 2.2 MPa. According to the IR analysis before and after the collagen was mineralized, it showed that: after the collagen was mineralized, the characteristic peaks of the collagen's amide I band showed red-shift, while the amide II band and the amide III band nearly disappeared, suggesting that chemical action occurred between the collagen and hydroxyapatite (HA), which should be the basis of the enhancement on the TTCP/MCPM bone cement caused by collagen; while according to the SEM and XRD patterns of the sample surface before and after the samples were immersed in SBF, it showed that: the immersion in SBF changed brushite (DCPD) into HA, at the same time, large number of new HA deposited, making the samples' surface more dense and smooth. It was not only the enhancement mechanism of immersion in SBF, but also showed the coagulating and hardening process of TTCP/MCPM bone cement was that: the DCPD was generated firstly, then it changed into HA.

Fujinaga K.,University of California at San Francisco | Barboric M.,University of Helsinki | Li Q.,Sichuan University | Luo Z.,University of California at San Francisco | And 3 more authors.
Nucleic Acids Research | Year: 2012

The positive transcription elongation factor b (P-TEFb) regulates RNA polymerase II elongation. In cells, P-TEFb partitions between small active and larger inactive states. In the latter, HEXIM1 binds to 7SK snRNA and recruits as well as inactivates P-TEFb in the 7SK snRNP. Several stimuli can affect this P-TEFb equilibrium. In this study, we demonstrate that protein kinase C (PKC) phosphorylates the serine at position158 (S158) in HEXIM1. This phosphorylated HEXIM1 protein neither binds to 7SK snRNA nor inhibits P-TEFb. Phorbol esters or the engagement of the T cell antigen receptor, which activate PKC and the expression of the constitutively active (CA) PKCθ protein, which is found in T cells, inhibit the formation of the 7SK snRNP. All these stimuli increase P-TEFb-dependent transcription. In contrast, the kinase-negative PKCθ and the mutant HEXIM1 (S158A) proteins block effects of these PKC-activating stimuli. These results indicate that the phosphorylation of HEXIM1 by PKC represents a major regulatory step of P-TEFb activity in cells. © 2012 The Author(s).

Wu W.,University of Sichuan | Yang X.,University of Sichuan | Pang Y.,Chongqing University of Posts and Telecommunications | Peng J.,Sichuan University | Jeon G.,Incheon National University
Optics Communications | Year: 2013

An image with all objects in focus is desired for human visual perception and computer vision tasks. The multifocus image fusion technique is a solution to fuse images acquired with different focus levels of a scene to obtain a clear fused image. Past approaches such as based on multiscale transformation (MST) are unavoidably lose information due to processing in transform domain and are sensitive to mis-registration. To solve these problems, we propose a hidden Markov model (HMM) based method, which not only uses patches rather than pixels as processing units but also handles each patch in the spatial domain instead of the transform domain. In the proposed method, firstly, the source images are divided into overlapping patches. Then, the fused image is modeled with HMM relying not only on the fidelity, clarity of patches but also on the relationship of adjacent patches. Subsequently, a belief propagation (BP) algorithm is adopted to select the fused patches from the source patches. Finally, these selected patches are integrated into the fused image. The experimental results prove that the proposed method achieves better performance, and is more robust to mis-registration than the MST-based methods. © 2012 Elsevier B.V.

Liu J.,University of Sichuan | Huang J.,University of Sichuan | He Y.,University of Sichuan | Liao B.,University of Sichuan | Liao G.,Sichuan University
Molecular Carcinogenesis | Year: 2014

microRNAs (miRNA) silence target genes through Watson-Crick based binding to the 3'untranslated regions (3'UTR). Thus, polymorphisms in the miRNA-binding sites may disrupt this process and play a potential role in cancer pathogenesis. Integrins have been implicated in the genesis and development of many tumors. This study was designed to evaluate the association between five SNP loci in predicted miRNA-binding sites in five integrin genes and prostate cancer occurrence and prognosis to provide data for screening high-risk Chinese Han individuals. These five polymorphisms were genotyped by using the high-resolution melting method (HRM) in 347 Chinese Han prostate cancer patients with long-time follow-up together with 367 age-matched healthy controls. GC carriers of rs11902171 in ITGAv were associated with a decreased risk of prostate cancer (OR 0.57, 95% CI 0.35-0.93). However, no significant difference was detected in genotype distributions of the five SNP loci in the progression-free survival time of prostate cancer. The ITGAv gene SNP rs11902171 may be potentially associated with the risk of prostate cancer. © 2012 Wiley Periodicals, Inc.

Polyakov D.,Sichuan University | Polyakov D.,Institute for Information Transmission Problems IITP
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We find a class of analytic solutions in open bosonic string field theory, parametrized by the chiral copy of higher spin algebra in AdS3. The solutions are expressed in terms of the generating function for the products of Bell polynomials in derivatives of bosonic space-time coordinates Xm(z) of the open string, the form of which is determined in this work. The products of these polynomials form a natural operator algebra realizations of w∞ (area-preserving diffeomorphisms), enveloping algebra of SU(2) and higher spin algebra in AdS3. The class of string field theory solutions found can, in turn, be interpreted as the "enveloping of enveloping," or the enveloping of AdS3 higher spin algebra. We also discuss the extensions of this class of solutions to superstring theory and their relations to higher spin algebras in higher space-time dimensions. © 2015 American Physical Society.

Li X.,Sichuan Normal University | Li X.,Sichuan University | Ji X.,Sichuan Normal University
Optics Communications | Year: 2013

The method to derive higher-order intensity moments of partially coherent beams propagating through an optical system in turbulence is proposed, and the simple expressions for intensity moments up to the fourth-order are derived. The results obtained in this paper are general, which can reduce readily to some interesting results as special cases. Taking the flat-topped beam as an example, higher-order intensity moments are studied in detail to illustrate the application of our general results. © 2013 Elsevier B.V. All rights reserved.

Zheng Y.,CAS Chengdu Institute of Biology | Peng R.,CAS Chengdu Institute of Biology | Peng R.,Sichuan University | Kuro-O M.,Hirosaki University | Zeng X.,CAS Chengdu Institute of Biology
Molecular Biology and Evolution | Year: 2011

In the practice of molecular dating, substitution saturation will bias the results if not properly modeled. Date estimates based on commonly used mitochondrial DNA sequences likely suffer from this problem because of their high substitution rate. Nevertheless, the patterns and extent of such expected bias remain unknown for many major evolutionary lineages, which often differ in ages, available calibrations, and substitution rates of their mitochondrial genome. In this case study of salamanders, we used estimates based on multiple nuclear exons to assess the effects of saturation on dating divergences using mitochondrial genome sequences on a timescale of ∼200-300 My. The results indicated that, due to saturation for older divergences and in the absence of younger effective calibration points, dates derived from the mitochondrial data were considerably overestimated and systematically biased toward the calibration point for the ingroup root. The overestimate might be as great as 3-10 times (about 20 My) older than actual divergence dates for recent splitting events and 40 My older for events that are more ancient. For deep divergences, dates estimated were strongly compressed together. Furthermore, excluding the third codon positions of protein-coding genes or only using the RNA genes or second codon positions did not considerably improve the performance. In the order Caudata, slowly evolving markers such as nuclear exons are preferred for dating a phylogeny covering a relatively wide time span. Dates estimated from these markers can be used as secondary calibrations for dating recent events based on rapidly evolving markers for which mitochondrial DNA sequences are attractive candidates due to their short coalescent time. In other groups, similar evaluation should be performed to facilitate the choice of markers for molecular dating and making inferences from the results. © 2011 The Author.

Gou J.,University of Electronic Science and Technology of China | Yi Z.,Sichuan University
Computer Journal | Year: 2013

In this article, we develop a linear supervised subspace learning method called locality-based discriminant neighborhood embedding (LDNE), which can take advantage of the underlying submanifold-based structures of the data for classification. Our LDNE method can simultaneously consider both 'locality' of locality preserving projection (LPP) and 'discrimination' of discriminant neighborhood embedding (DNE) in manifold learning. It can find an embedding that not only preserves local information to explore the intrinsic submanifold structure of data from the same class, but also enhances the discrimination among submanifolds from different classes. To investigate the performance of LDNE, we compare it with the state-of-the-art dimensionality reduction techniques such as LPP and DNE on publicly available datasets. Experimental results show that our LDNE can be an effective and robust method for classification. © 2013 The Author.

Kang Y.,Tsinghua University | Zhou L.,Tsinghua University | Li X.,Sichuan University | Yuan J.,Tsinghua University
Journal of Materials Chemistry | Year: 2011

β-Cyclodextrin-modified hybrid magnetic nanoparticles (Fe 3O4@SiO2-PGMACD) were synthesized via the combination of atom transfer radical polymerization on the surfaces of silica coated iron oxide particles (Fe3O4@SiO2) and ring-opening reaction of epoxy groups. The feasibility of using Fe 3O4@SiO2-PGMACD as separable immobilized catalyst and adsorbent was demonstrated. It was found: (1) the prepared Fe 3O4@SiO2-PGMACD could be used as catalyst in substrate-selective oxidation of alcohols system and the catalytic efficiency was close to pure β-Cyclodextrin of equal quantity; (2) the resulting particles appeared remarkably dominant adsorption capacity compared with poly(glycidyl methacrylate) grafted magnetic nanoparticles (Fe3O 4@SiO2-PGMA) in the removal of bisphenol A from aqueous solutions. The results suggest that the novel fabricated nanoparticles could serve as bifunctional materials in catalysis or adsorption and subsequently become potential multifunctional materials. © The Royal Society of Chemistry 2011.

Polyakov D.,Sichuan University | Polyakov D.,Sogang University | Polyakov D.,Institute for Information Transmission Problems IITP
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We construct analytic solutions in cubic open superstring field theory at higher superconformal ghost numbers. The solutions are the pure ghost ones, given by combinations of Bell polynomials of bosonized superconformal ghost fields multiplied by exponents of the bosonized ghosts. Based on the structure of the solutions, we conjecture them to describe the ghost part of collective vacuum for higher spin modes in open string theory. © 2014 American Physical Society.

Zhang J.,University for Business Studies | Zhang D.,Sichuan University
IEEE Signal Processing Letters | Year: 2010

Studies show that no detectors for LSB matching have yet proven universally reliable and it is hard to predict which types of image are suitable for a specific steganalyzer. For the kind of decompressed images, this paper presents an efficient steganalyzer that exploits the fact that the noise residuals in the DCT domain are rather concentrated on zero and very sensitive to LSB matching. Experimental results show that it is almost perfect at embedding rate 0.5 bpp and that it is the accuracy of 90.9% at 0.1 bpp against the accuracy of 44.6% with the WAM steganalyzer. However, the proposed detector works only as long as the exact JPEG decompressor is known. © 2009 IEEE.

Bilotti E.,Queen Mary, University of London | Zhang R.,Queen Mary, University of London | Deng H.,Queen Mary, University of London | Deng H.,Sichuan University | And 3 more authors.
Journal of Materials Chemistry | Year: 2010

In this study, thermoplastic polyurethane (TPU) fibres containing multi-walled carbon nanotubes (MWNTs) and fabricated via an extrusion process were demonstrated to possess a tuneable level of electrical conductivity. A simple approach based on the time-temperature superposition applied to the electrical conductivity of carbon nanotube (CNT) percolating in a thermoplastic polyurethane (TPU) melt was also developed to predict the conductivity of the nanocomposite fibres. The observation of Arrhenius dependence of zero-shear viscosity and the assumption of simple inverse proportionality between the variation of conductivity, due to network formation, and viscosity allow a universal plot of time variation of conductivity to be composed, which is able to predict the conductivity of the extruded fibres. The same TPU/CNT fibres were also demonstrated to possess good strain sensing abilities, which makes them good candidates for applications in smart textiles. © 2010 The Royal Society of Chemistry.

Wu H.,Nanyang Technological University | Wu H.,Sichuan University | Ng B.S.H.,Nanyang Technological University | Thibault G.,Nanyang Technological University
Bioscience Reports | Year: 2014

Stress pathways monitor intracellular systems and deploy a range of regulatory mechanisms in response to stress. One of the best-characterized pathways, the UPR (unfolded protein response), is an intracellular signal transduction pathway that monitors ER (endoplasmic reticulum) homoeostasis. Its activation is required to alleviate the effects of ER stress and is highly conserved from yeast to human. Although metazoans have three UPR outputs, yeast cells rely exclusively on the Ire1 (inositol-requiring enzyme-1) pathway, which is conserved in all Eukaryotes. In general, the UPR program activates hundreds of genes to alleviate ER stress but it can lead to apoptosis if the system fails to restore homoeostasis. In this review, we summarize the major advances in understanding the response to ER stress in Sc (Saccharomyces cerevisiae), Sp (Schizosaccharomyces pombe) and humans. The contribution of solved protein structures to a better understanding of the UPR pathway is discussed. Finally, we cover the interplay of ER stress in the development of diseases. © 2014 The Author(s).

Chen N.,Tsinghua University | Wang Q.,Tsinghua University | Zhao W.,Tsinghua University | Lin S.-T.,Sichuan University | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

We show that exothermic isospin-violating dark matter (IVDM) can make the results of the latest CDMS-Si experiment consistent with recent null experiments, such as XENON10, XENON100, LUX, CDEX, and SuperCDMS, whereas for the CoGeNT experiment, a strong tension still persists. For CDMS-Si, separate exothermic dark matter or isospin-violating dark matter cannot fully ameliorate the tensions among these experiments; the tension disappears only if exothermic scattering is combined with an isospin-violating effect of fn/fp=-0.7. For such exothermic IVDM to exist, at least a new vector gauge boson (dark photon or dark Z') that connects SM quarks to Majorana-type DM particles is required. © 2015 The Authors.

Huang X.,University of Sichuan | Wang Y.,University of Sichuan | Liao X.,University of Sichuan | Shi B.,Sichuan University
Journal of Hazardous Materials | Year: 2010

Tannin is well known to be an inexpensive and ubiquitous natural biomass, which has high chelating affinity towards many metal ions. In this study, bayberry tannin (BT) was immobilized on mesoporous silica matrix to prepare a novel adsorbent, which was subsequently used for the adsorptive recovery of Au3+ from aqueous solutions. It was found that bayberry tannin-immobilized mesoporous silica (BT-SiO2) was able to effectively recover Au3+ from acidic solutions (pH 2.0). The equilibrium adsorption capacity of Au3+ on BT-SiO2 was high up to 642.0mg/g at 323K. Due to its mesoporous structure, BT-SiO2 exhibited an extremely fast adsorption rate to Au3+ as compared with other tannin gel adsorbent. The presence of other coexisting metal ions, such as Pb2+, Ni2+, Cu2+ and Zn2+, did not decrease the adsorption capacity of Au3+ on BT-SiO2, and BT-SiO2 had almost no adsorption capacity to these coexisting metal ions, which suggested the high adsorption selectivity of BT-SiO2 to Au3+. Additionally, about 73% of adsorbed Au3+ can be desorbed using aqua regia, and the Au3+ solution was concentrated about 18.0 times as compared with the original solution. Consequently, the outstanding characteristics of BT-SiO2 provide the possibility of effective recovery and concentration of Au3+ from diluted solutions. © 2010.

Wei Y.,University of Sichuan | Zhang J.,University of Sichuan | Wang X.,University of Sichuan | Duan Y.,Sichuan University
Biosensors and Bioelectronics | Year: 2015

This paper describes a novel approach utilizing nano-graphite-aptamer hybrid and DNase I for the amplified detection of ochratoxin A (OTA) for the first time. Nano-graphite can effectively quench the fluorescence of carboxyfluorescein (FAM) labeled OTA specific aptamer due to their strong π-. π; stacking interactions; while upon OTA addition, it will bind with aptamer to fold into an OTA-aptamerG-quadruplex structure, which does not adsorb on the surface of nano-graphite and thus retains the dye fluorescence. Meanwhile, the G-quadruplex structure can be cleaved by DNase I, and in such case OTA is delivered from the complex. The released OTA then binds other FAM-labeled aptamers on the nano-graphite surface, and touches off another target recycling, resulting in the successive release of dye-labeled aptamers from the nano-graphite, which leads to significant amplification of the signal. Under the optimized conditions, the present amplified sensing system exhibits high sensitivity toward OTA with a limit of detection of 20. nM (practical measurement), which is about 100-fold higher than that of traditional unamplified homogeneous assay. Our developed method also showed high selectivity against other interference molecules and can be applied for the detection of OTA in real red wine samples. The proposed assay is simple, cost-effective, and might open a door for the development of new assays for other biomolecules. This aptasensor is of great practical importance in food safety and could be widely extended to the detection of other toxins by replacing the sequence of the recognition aptamer. © 2014 Elsevier B.V.

Wei D.,Sichuan University
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2012

In order to investigate the effects of HA whisker and carboxymethyl chitosan-gelatin(CMC-Gel) on the mechanical properties of porous calcium phosphate cement, a series of alpha-tricalcium phosphate (alpha-TCP), HA whisker and L-sodium glutamate porogen with different mass fractions were mixed, and setting liquid was added to them to prepare alpha-TCP/HA whisker composite porous bone cement. Then, the cement was immersed in a series of CMC-Gel solutions which had different weight ratios of CMC to Gel to prepare alpha-TCP/HA whisker/CMC-Gel composite porous bone cement. The compressive strengths and microstructure of cement were characterized by mechanical testing machine and SEM. The results showed that when the mass fraction of HA whisker is 4%, the compressive strength of alpha-TCP/HA whisker composite porous bone cement reaches 2.57MPa, which is 1.81 times that of alpha-TCP bone cement. When the weight ratio of CMC to Gel is 50:50, the compressive strength of alpha-TCP/HA whisker/CMC-Gel composite porous bone cement is 3. 34MPa, which is 2.35 times that of alpha-TCP bone cement, and the toughness of the composite cement is greatly improved as well.

Ren S.,Sichuan University | Ren S.,University of Liverpool | Dawson R.,University of Liverpool | Adams D.J.,University of Liverpool | Cooper A.I.,University of Liverpool
Polymer Chemistry | Year: 2013

Low band-gap conjugated microporous polymers (CMPs) based on benzothiadiazole (BTZ) and thiophene-benzothiadiazole-thiophene (TBT) functional groups are prepared. The polymers show moderate surface areas and broad light absorption covering the whole visible light region. Fluorescence of one of the polymers can be readily quenched by the in situ blending of fullerene. This journal is © The Royal Society of Chemistry.

He J.,Huazhong University of Science and Technology | Xiao J.,Nankai University | Shao Z.,Sichuan University
Acta Mathematica Scientia | Year: 2014

Membrane algorithms (MAs), which inherit from P systems, constitute a new parallel and distribute framework for approximate computation. In the paper, a membrane algorithm is proposed with the improvement that the involved parameters can be adaptively chosen. In the algorithm, some membranes can evolve dynamically during the computing process to specify the values of the requested parameters. The new algorithm is tested on a well-known combinatorial optimization problem, the travelling salesman problem. The empirical evidence suggests that the proposed approach is efficient and reliable when dealing with 11 benchmark instances, particularly obtaining the best of the known solutions in eight instances. Compared with the genetic algorithm, simulated annealing algorithm, neural network and a fine-tuned non-adaptive membrane algorithm, our algorithm performs better than them. In practice, to design the airline network that minimize the total routing cost on the CAB data with twenty-five US cities, we can quickly obtain high quality solutions using our algorithm. © 2014 Wuhan Institute of Physics and Mathematics. Published by Elsevier Ltd. All rights reserved.

Xiao D.-Q.,Sichuan University
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2012

Piezoelectric ceramics and devices are very important and essential from the viewpoints of applications in various aspects. The development of lead-free piezoelectric ceramics with high performance, which properties could be comparable to their lead-based counters, is basically important because of the demand of the sustainable development of the world, the environmental protection and the safety concerns. The author and his group have been engaged in the researches of perovskite lead-free piezoelectric ceramics, especially the (Bi1/2Na1/2) TiO3 (BNT) and (K1/2Na1/2) NbO3 (KNN) ceramics, for more than ten years. In present paper, mainly based on the research results in the authors group, the research progresses of the composition design, phase structure and it's relation to materials properties, ceramics doping and its effects for the materials properties, temperature stability of the ceramics and its mechanism, and the techniques newly developed for the synthesis and preparation for BNT and KNN ceramics are outlined; and the device applications of the ceramics are roughly introduced. Based on the authors considerations and the recent development on lead-free piezoelectric ceramics worldwide, some prospects for further development of perovskite lead-free piezoelectric ceramics in coming years are also pointed out.

Lin H.,Sichuan University
Proceedings - 4th International Conference on Genetic and Evolutionary Computing, ICGEC 2010 | Year: 2010

In this paper, we focus on the problem of predicting sensitive relationships from Email corpus. We refer to the problem of predicting sensitive relationships from a social network as link re-identification. We propose a predicting sensitive relationships method which has two steps. First step is counting mutual privacy communication. Second step is evaluation cluster factor. Experimental results on Enron email corpus are presented to support our analysis. © 2010 IEEE.

Sun H.,Sichuan University
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica | Year: 2012

Lamiophlomis rotata is a common wild herb in Tibetan traditional medicine with important medicinal and economic value. The paper examines the wild distributions, exploitation regime, and situations. A variety of research methods, such as literature survey, specimens inspection, market information collection in major Chinese herbal markets, questionnaire of herbalists and employers of local governments and institutions, and field quadrat survey and AcrGIS as well, have been used for this work. Total stock of wild resources of L. rotata is ranging from 3 713.49 tons to 6 896.56 tons (2 519-3 314 t in Qinghai, 490-1 414 t in Gansu, 641-1 167 t in Sichuan, and 422-999 t in Tibet, respectively), acceptable harvest quantity of the herb is ranging from 908-1 675 t per year, and actual harvest quantity is 2 520 t annually far beyond the acceptable harvest quantity. Harvesting quantity of L. rotata is far more than that of acceptable, suggesting that utilization pattern of this wild resource plant is unsustainable. L. rotata seems to act as an indicating plant of degraded ecosystem of high-altitude grassland, shrub grassland, and wetland, and distributes in those degraded and degrading plateau ecosystems, and the plant is facing with pressure of ecological protection and wild resource population degradation. Wild population monitoring and standard cultivation are of importance for although they are far from implementation due to shortage of related basic studies.

Wang H.,Sichuan University
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2015

The classical research cases, which have greatly promoted the development of genetics in history, can be combined with the content of courses in genetics teaching to train students' ability of scientific thinking and genetic analysis. The localization and clone of gene controlling tomato fruit weight is a pioneer work in quantitative trait locus (QTL) studies and represents a complete process of QTL research in plants. Application of this integrated case in genetics teaching, which showed a wonderful process of scientific discovery and the fascination of genetic research, has inspired students' interest in genetics and achieved a good teaching effect.

Huang Y.,Nanjing Southeast University | Lu X.,Nanjing Southeast University | Qian W.,Nanjing Southeast University | Tang Z.,Nanjing Southeast University | Zhong Y.,Sichuan University
Acta Biomaterialia | Year: 2010

Reflectometry interference spectroscopy (RIfS) is known as a highly sensitive and robust technique for direct, label-free detection of the interaction of biomacromolecules in real time and in situ. The aim of the present study was to investigate the competitive protein adsorption on the surface of fluorocarbon end-capped poly(carbonate) urethane (PCUF) and polystyrene (PS) based on the RIfS method. The surface energy and microstructures of PCUF and PS were characterized by contact angle measurement and atomic force microscopy. Interfacial energies between these surfaces and the proteins were then calculated. The protein adsorption experiments were carried out with both single solution and ternary solutions composed of albumin, fibrinogen and immunoglobulin-G (IgG). The results of surface characterization showed that PCUF was more hydrophilic than PS with a smaller surface energy, and micro-phases separation of PCUF was observed. RIfS analysis results revealed that more albumins, less fibrinogen and IgG were detected on the PCUF surface compared with PS after simplex and competitive protein adsorption, which indicated that PCUF had a preferential adsorption for albumin. The special morphology, smaller surface energy and calculated interfacial energies between PCUF and proteins may be responsible for the better blood compatibility of PCUF compared to PS. The results suggest that RIfS could serve as a novel, effective method for studying the competitive protein adsorption on biomaterial surfaces. © 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Zainal Abidin I.,Newcastle University | Yun Tian G.,Newcastle University | Wilson J.,Newcastle University | Yang S.,Sichuan University | Almond D.,University of Bath
NDT and E International | Year: 2010

Pulsed eddy current (PEC) thermography employs a combination of PEC and thermographic non-destructive testing (NDT) techniques. This study considers the capabilities of PEC thermography for obtaining quantitative information about cracks set at an angle to the surface. The investigation is implemented by simulating the transient thermal distribution for angular slots, via time-stepping 3D finite element analysis (FEA), with the experimental work undertaken for verification. A slope inclination feature of the transient temperature distribution has been extracted and presented for estimating the angle of slots that is independent of slot depth and length inside the sample. With the identification of the slot angle, quantification of the length/depth of the slot inside the sample can then be made through a maximum temperature amplitude feature. Experimental studies have been undertaken for evaluation of the numerical simulation and transient feature extraction methods. © 2010 Elsevier Ltd.

Miyamoto Y.,NEC Corp | Miyamoto Y.,Japan Science and Technology Agency | Zhang H.,Sichuan University | Tomanek D.,Michigan State University
Physical Review Letters | Year: 2010

We propose to use ultrashort laser pulses to detach intact graphene monolayers from a graphite surface, one at a time. As suggested by a combination of real-time ab initio time-dependent density functional calculations for electrons with molecular dynamics simulations for ions, this athermal exfoliation process follows exposure to femtosecond laser pulses with a wavelength of 800 nm and the full width at half maximum (FWHM) of 45 fs. Shorter pulses (FWHM=10fs) with the same wavelength and intensity speed up the exfoliation and cause transient contraction in subsurface layers. Photoexfoliation should be capable of producing intact graphene monolayers free of contaminants and defects at a high rate. © 2010 The American Physical Society.

To improve the hemocompatibility of polyurethanes, an amine monomer containing a long fluorine tail and phosphatidylcholine polar headgroups, 2-amino-3-oxo-3-(2-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctan amido) ethyl amino) propyl phosphorylcholine (FASPC) was firstly synthesized and characterized. Then four kinds of fluorinated phosphatidylcholine end-capped polyurethanes with different chemical structures were prepared. The surface properties of these prepared polyurethanes were characterized using X-ray photoelectron spectroscopic analysis (XPS) and water contact angle measurements. The results indicated that the phosphatidylcholine (PC) polar headgroups along with the fluorine tail could be easily enriched on the top surfaces, and the PC groups could be highly oriented on the outmost surface when the polymer film was in contact with water for only 30 s at room temperature. The evaluation of hemocompatibity was carried out via fibrinogen adsorption and platelet adhesion. Fibrinogen adsorption (37°C for 90 min) decreased by 98% to 87% compared to that on ordinary polyurethane surfaces, and almost no platelet adhesion and activation was observed at 37°C for 2 h.

Chen Z.,Southwest Jiaotong University | Zhou Q.,Sichuan University | Xu J.,Southwest Jiaotong University
IET Power Electronics | Year: 2015

DC-DC converters with high-voltage gain and low-input current ripple have attracted much attention in photovoltaic, fuel cells and other renewable energy system applications. Conventional boost-flyback converter can achieve high-voltage set-up ratio; however, its input current is pulsing and the voltage stress across output diode of flyback-cell is high. In this study, by incorporating coupled-inductor into the boost-cell of boost-flyback converter, the voltage stress across the output diode is effectively reduced. Passive snubber circuit is utilised to suppress the voltage spike across power switch, low-voltage-rated metal-oxide semiconductor field effect transistor (MOSFET) with low Rds_on can thus be used to reduce the conduction loss of power MOSFET. In addition, ripple-free input current can be achieved, which makes the design of electromagnetic interference filter easy. Steady-state characteristics of the proposed converter are analysed, and experimental results are given to verify the analysis results. © The Institution of Engineering and Technology 2015.

Liu L.,Sichuan University
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2012

As a method of dosimetric verification in radiotherapy, gamma index has been widely used for evaluating dose distribution in research and clinical cases. However, for three-dimensional dose distributions, gamma index calculation is very time consuming for the computers. In this paper, based on a pre-sorting technique, we implement a parallel computing algorithm of gamma index on graphic processing unit (GPU). Dose comparisons are performed for seven cases to test our new implementation. It was shown that the GPU-based gamma index calculations achieved a speedup of ten-folds in comparison with corresponding CPU implementation without losing accuracy. The result showed that utilizing GPU parallel computing to speed up gamma index calculations could be reliable and efficient in the implementation.

Wang H.,University of Sichuan | He D.,University of Sichuan | He D.,Sichuan University
High Pressure Research | Year: 2012

A hybrid pressure cell of pyrophyllite and magnesium oxide (HPCPM) used in large volume cubic presses is presented. In the HPCPM, a cubic frame which is made of pyrophyllite with face-centered square holes works as gaskets, and a heteromorphosis magnesium oxide works as the pressure-transmitting medium. Our experimental results indicated that the pressure-generation efficiency using the HPCPM was improved by about 40% than that using the traditional pyrophyllite pressure cell without decreasing the anvil truncation size (without sacrificing the sample volume). The HPCPM could pressurize samples of 1000mm 3 volume up to about 8GPa, which is significantly higher than that available using the traditional pressure cell, which reports a highest pressure of about 6GPa. © 2012 Taylor & Francis.

Fu Z.,Sichuan University
Journal of High Energy Physics | Year: 2012

We present a direct lattice QCD calculation of the κ meson decay width using the s-wave scattering phase shift for the isospin I = 1/2 pion-kaon (πK) system. In the moving frame, we employ a special finite size formula, which is the πK system's Rummukainen-Gottlieb formula, to calculate the scattering phase shifts which demonstrate a characteristic consistent with the presence of a resonance around π meson mass. The effective range formula is adopted to describe the phase-shift dependence and we extract the effective κ → πK coupling constant gκπK = 4.54(76)GeV. The decay width estimated from phase shift is about 293±101MeV, which is reasonably near to the values of the recent experimental measurements. Our preliminary lattice simulations are carried out with the MILC full QCD gauge configurations in the presence of 2 + 1 flavors of the "Asqtad" improved staggered dynamical sea quarks on a 16 3 × 48 lattice at (m π + mK)/mκ ≈ 0.8 and lattice spacing α ≈ 0.15 fm. © SISSA 2012.

Ali S.S.,University of Graz | Ali S.S.,Biocenter Linz | Yu Y.,Sichuan University | Pfosser M.,Biocenter Linz | Wetschnig W.,University of Graz
Annals of Botany | Year: 2012

•Background and Aims: Subfamily Hyacinthoideae (Hyacinthaceae) comprises more than 400 species. Members are distributed in sub-Saharan Africa, Madagascar, India, eastern Asia, the Mediterranean region and Eurasia. Hyacinthoideae, like many other plant lineages, show disjunct distribution patterns. The aim of this study was to reconstruct the biogeographical history of Hyacinthoideae based on phylogenetic analyses, to find the possible ancestral range of Hyacinthoideae and to identify factors responsible for the current disjunct distribution pattern.•Methods: Parsimony and Bayesian approaches were applied to obtain phylogenetic trees, based on sequences of the trnL-F region. Biogeographical inferences were obtained by applying statistical dispersal-vicariance analysis (S-DIVA) and Bayesian binary MCMC (BBM) analysis implemented in RASP (Reconstruct Ancestral State in Phylogenies).•Key Results: S-DIVA and BBM analyses suggest that the Hyacinthoideae clade seem to have originated in sub-Saharan Africa. Dispersal and vicariance played vital roles in creating the disjunct distribution pattern. Results also suggest an early dispersal to the Mediterranean region, and thus the northward route (from sub-Saharan Africa to Mediterranean) of dispersal is plausible for members of subfamily Hyacinthoideae.•Conclusions: Biogeographical analyses reveal that subfamily Hyacinthoideae has originated in sub-Saharan Africa. S-DIVA indicates an early dispersal event to the Mediterranean region followed by a vicariance event, which resulted in Hyacintheae and Massonieae tribes. By contrast, BBM analysis favours dispersal to the Mediterranean region, eastern Asia and Europe. Biogeographical analysis suggests that sub-Saharan Africa and the Mediterranean region have played vital roles as centres of diversification and radiation within subfamily Hyacinthoideae. In this bimodal distribution pattern, sub-Saharan Africa is the primary centre of diversity and the Mediterranean region is the secondary centre of diversity. Sub-Saharan Africa was the source area for radiation toward Madagascar, the Mediterranean region and India. Radiations occurred from the Mediterranean region to eastern Asia, Europe, western Asia and India. © The Author 2011.

Fu Z.,University of Sichuan | Fu Z.,Sichuan University
Journal of High Energy Physics | Year: 2012

We report an exploratory lattice QCD investigation of the σ meson decay width though the s-wave scattering phase shift for isospin I = 0 pion-pion (ππ) system. Rummukainen-Gottlieb formula is used to estimate the scattering phase for the two-pion system in the moving frame, which demonstrate the presence of a resonance around σ meson. Using the effective range formula we extract the effective σ → ππ coupling constant as g σππ = 2.69(44) GeV, which is consistent with the theoretical predictions. The estimated decay width is about 236 ± 49MeV. These simulations are carried out on a 16 3 x 48 MILC gauge configuration with the N f = 2 + 1 flavor of the "Asqtad" improved staggered dynamical sea quarks at m π/m σ ≈ 0.414 and the lattice spacing a ≈ 0.15 fm. © SISSA 2012.

Zhang L.,Sichuan University | Li S.,University of Sichuan
Nonlinear Analysis: Real World Applications | Year: 2015

This paper concerns the conditional global regularity of incompressible MHD equations with horizontal dissipation and horizontal magnetic diffusion in two dimension. When only horizontal dissipation and horizontal magnetic diffusion are present, there is no control on the vertical derivatives of velocity field and magnetic field, which is the main difficulty to establish the global regularity. In this paper, we establish a global regularity criterion in terms of one entry of the velocity gradient tensor or one entry of the magnetic field gradient tensor, which extends the recent work (Fan and Ozawa, 2014). © 2014 Elsevier Ltd. All rights reserved.

Liu Y.Y.,Sichuan University | Lu Z.,Cornell University
Progress in Electromagnetics Research | Year: 2011

A theoretical study of optical properties of phase shift defects in one-dimensional asymmetrical photonic structures consisting of two rugate segments with different periodicities at both normal and oblique incidence is presented. Using the propagation matrix method we numerically calculated transmittance spectra, defect wavelengths, energy density distributions, and group velocities for TE and TM waves, respectively. Our study shows that by adjusting the periodicity of one rugate segment, the defect wavelengths can be shifted toward either a shorter wavelength or a longer wavelength. The differences of the energy density distributions of TE and TM waves at different angles of incidence are explained with the help of group velocity. Effects of the change of the period of one rugate segment on the peak energy densities of defect modes and minimum group velocities at different angles of incidence are also investigated.

Han J.,Sichuan University | Liu H.,University of Miami
Journal of Power Sources | Year: 2014

Methanol crossover is a serious problem for a direct methanol fuel cell (DMFC) since it causes mixed potential and waste of fuel. The amount of methanol crossover directly depends on the methanol concentration at the interface between the anode catalyst layer and the electrolyte membrane. However, no technique is available to measure the methanol concentration at this interface in an operating DMFC. Previous experimental results show that sharp peaks exist in the methanol crossover flux when the cell voltage changes abruptly [1]. Systematic studies on these peaks reveal the formation mechanisms. Furthermore, a novel method to determine the methanol concentration at the interface between the anode catalyst layer and the Nafion® electrolyte membrane is developed. Finally, the relationship between the methanol concentration at this interface and the drag coefficients for methanol and water in an operating DMFC are also derived. © 2014 Elsevier B.V. All rights reserved.

Miyamoto Y.,Japan National Institute of Advanced Industrial Science and Technology | Zhang H.,Sichuan University
Materials Express | Year: 2012

We present energy increase in condensed matters upon irradiation with short pulse laser shot determined by the first-principles simulation based on the time-dependent density functional theory. The laser-field is expressed by time-varying scalar potential with sawtooth type spatial variation within the periodic boundary conditions. With this scheme, the transferred energy by the laser-field (electric field) is defined as total-energy increase at the time when the laser-field vanishes. Then the amount of increase is found to be dependent not only on field intensity but also on vacuum thickness of the repeating slab model. The thickness dependence can be attributed with wider range of the scalar potential that expresses the laser-field with deeper vacuum thickness. The wider potential range increases amplitude of electroncloud oscillation induced by the pulse laser causing higher energy increase in materials. To obtain converged quantity in laser fluence, we conclude a large vacuum region is necessary. © 2012 by American Scientific Publishers All rights reserved.

Li X.,Sichuan Normal University | Li X.,Sichuan University | Ji X.,Sichuan Normal University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2014

This paper studies the propagation characteristics related to higher-order moments of decentered annular beams through non-Kolmogorov turbulence. The analytical expressions for the mean-squared beam width w, the skewness parameter A, and the kurtosis parameter K are derived. The analytical expression for the non-Kolmogorov turbulence parameter T0 is also derived, and the differences between two non-Kolmogorov turbulence parameters T0 and T are examined. It is shown that K depends on both T and T0, but w and A only depend on T. K decreases monotonically as the spectral power law exponent a increases, but there exist a maximum of w and a minimum of A when a - 3.112. When propagation distance z is long enough, A reaches zero, i.e., the intensity distribution is perfectly symmetric about the centroid position axis. In free space, both A < 0 and A > 0 may appear on propagation. However, it is always A < 0 or A > 0 on propagation when turbulence is not weak. On the other hand, in turbulence, the maximum of K increases as the decentered parameter increases and the obscure ratio decreases. In particular, when z is long enough, the beam spot is elliptical in free space, but it becomes circular in turbulence. © 2013 Optical Society of America.

Kwok A.H.Y.,University of Hong Kong | Wang Y.,Sichuan University | Leung F.C.,University of Hong Kong
General and Comparative Endocrinology | Year: 2012

Prostaglandins E (PGE) and F (PGF) mediate diverse physiological functions via their cell surface receptors - prostaglandin E receptor (EP) subtypes 1, 2, 3 and 4 (EP1; EP2; EP3; EP4) and F receptor (FP). In teleost fishes, PGE was implicated in gill epithelium ion transport, while both PGE and PGF were involved in oocyte maturation, follicular rupture and coordination of reproductive behaviors. However, little is known about the mechanisms behind their actions. In present study, we first identified the full-length ORF cDNA clones of three zebrafish prostaglandin E receptor subtype 1 (zEP1) isoforms - zEP1a, zEP1b and zEP1c - and FP (zFP) from adult ovary. RT-PCR showed that zEP1a, zEP1b and zFP are widely expressed in adult tissues, while zEP1c mRNA expression is mainly confined in brain and kidney. Using a pGL3-NFAT-RE luciferase reporter system, both zEP1a and zEP1b expressed in DF-1 cells were shown to be activated by PGE2 potently while zEP1c and zFP were activated by PGF2a effectively, suggesting that the four receptors are functionally coupled to intracellular Ca2+-signaling pathway. Furthermore, EP1a and EP1b, but not EP1c were suggested to couple to cAMP-PKA signaling pathway using a pGL3-CRE luciferase reporter assay. Although zEP1c might originate as a paralog to zEP1a and zEP1b, its functional coupling to PGF2α instead of PGE2 suggested that zEP1 isoforms might have sub-functionalized in their ligand binding and G protein coupling specificity, in addition to differential tissue distribution. Characterization of these receptors undoubtedly furthered our understanding on the diverse yet highly target-specific responses of prostaglandins in teleosts. © 2012 Elsevier Inc.

Mu C.,University of Sichuan | Zhang K.,University of Sichuan | Lin W.,Sichuan University | Li D.,University of Sichuan
Journal of Biomedical Materials Research - Part A | Year: 2013

Polymeric genipin macromers, prepared by ringopening polymerization at various pH values, are used as crosslinking agents to fix collagen hydrogels. The results indicate that as the dark color of polymeric genipin itself and the networks formed by long-range intermolecular crosslinking, the genipin-fixed collagen hydrogels displace darker color. The polymeric genipin prepared at higher pH value needs longer time to fully crosslink with collagen molecules. Moreover, polymerization of genipin reduces the yield of genipin-fixed collagen hydrogels due to low extent of crosslinking. Specially, the microscope photographs present the porous networks structures of genipin-fixed collagen hydrogels. The pore size increases with the increase in polymerization degree of genipin. The data of FTIR indicate the likely transition of -NH2 groups in collagen chains into C=N. Owning to much more number of hydrophilic groups and more porous networks, collagen hydrogels fixed by genipin with higher polymerization degree have higher water absorption capacity. The equilibrium swelling of genipin-fixed collagen hydrogels is pH-responsive, which show "M" type changes with the pH values. The results obtained in the study suggest that the polymeric genipin prepared at various pH values lead to significant influence to the crosslinking characteristics and properties of collagen hydrogels. © 2012 WILEY PERIODICALS, INC.

Miyamoto Y.,NEC Corp | Zhang H.,Sichuan University | Rubio A.,University of the Basque Country
Physical Review Letters | Year: 2010

We show by first-principles simulations that ultrafast laser pulses induce different chemical reactions in a molecule trapped inside a nanotube. A strong laser pulse polarized perpendicular to the tube axis induces a giant bond stretch of an encapsulated HCl molecule in semiconducting carbon nanotube or in a BN nanotube. Depending on the initial orientation of the HCl molecule, the subsequent laser-induced dynamics is different: either complete disintegration or rebonding of the HCl molecule. Radial motion of the nanotube is always observed and a vacancy appears on the tube wall when the HCl is perpendicular to the tube axis. Those results are important to analyze confined nanochemistry and to manipulate molecules and nanostructures encapsulated in organic and inorganic nanotubes. © 2010 The American Physical Society.

Zhang Y.-X.,University of Electronic Science and Technology of China | Qiao S.,University of Electronic Science and Technology of China | Huang W.,Sichuan University | Ling W.,University of Electronic Science and Technology of China | And 2 more authors.
Applied Physics Letters | Year: 2011

This paper presents the design, simulation, and measurement of an asymmetric triple-band metamaterial composed of single geometry electric field coupled resonators in the terahertz region. Theoretical and experimental results show that the structure has three distinct and strong absorption frequency peaks near 0.38, 0.58, and 0.74 THz, all of which are related to the inductance-capacitance resonance of the metamaterial. Due to the well-separating of different resonances in the particle, this metamaterial shows potentially application promises in the design of multiband terahertz devices. © 2011 American Institute of Physics.

Yao J.X.,Sichuan University
Applied Mechanics and Materials | Year: 2014

This paper provided a method and implementation technique about massive amount of data information transmission based on a variety of problems of the UDP communication in poor network. We provided a method based on several deficiencies of traditional method, which could remove the task that would keep the data package transmission in the correct order to receiver in order to reduce the communication burden and improve the stability and efficiency of transmission. A large number of actual tests proved that the improve protocol can transmit the massive amount of data information good although the network speed is below 10K/S which showed the practical value. © (2014) Trans Tech Publications, Switzerland.

Guo F.,Institute of Atomic and Molecular Physics | Cheng X.-L.,Institute of Atomic and Molecular Physics | Zhang H.,Sichuan University
Journal of Physical Chemistry A | Year: 2012

Which is the first step in the decomposition process of nitromethane is a controversial issue, proton dissociation or C-N bond scission. We applied reactive force field (ReaxFF) molecular dynamics to probe the initial decomposition mechanisms of nitromethane. By comparing the impact on (010) surfaces and without impact (only heating) for nitromethane simulations, we found that proton dissociation is the first step of the pyrolysis of nitromethane, and the C-N bond decomposes in the same time scale as in impact simulations, but in the nonimpact simulation, C-N bond dissociation takes place at a later time. At the end of these simulations, a large number of clusters are formed. By analyzing the trajectories, we discussed the role of the hydrogen bond in the initial process of nitromethane decompositions, the intermediates observed in the early time of the simulations, and the formation of clusters that consisted of C-N-C-N chain/ring structures. © 2012 American Chemical Society.

Tian Y.-H.,Los Alamos National Laboratory | Tian Y.-H.,Sichuan University | Pierpont A.W.,Los Alamos National Laboratory | Batista E.R.,Los Alamos National Laboratory
Inorganic Chemistry | Year: 2014

Recently, Nishibayashi et al. reported a dimolybdenum-dinitrogen complex that is catalytic for complete reduction of dinitrogen to ammonia. This catalyst is different from the Schrock molybdenum catalyst in two fundamental aspects: it contains two metal centers, and the oxidation state is Mo0 instead of MoIII. We show that a remarkable feature of the bimetallic complex is the bond-mediated delocalized electronic states, resulting from the two metal centers bridged by a dinitrogen ligand. Using first-principles calculations, we found that this property makes the bimetallic complex the effective catalyst, as opposed to the originally postulated monometallic fragment. A favorable reaction pathway is identified, and the nature of the intermediates is examined. Furthermore, studies of the intermediate states led us to propose possible deactivation processes of the catalyst. The finding that the central bimetallic unit (Mo-N2-Mo) is relevant for catalytic activity may provide a guideline for the development of more efficient dinitrogen-reducing catalysts. © 2014 American Chemical Society.

Hu X.,Sichuan University
Guangxue Xuebao/Acta Optica Sinica | Year: 2012

Characteristics and laws of the variation of self-mixing interference signal of laser diode along with the increase of external-cavity length are analyzed theoretically. The self-mixing interference signal attenuating exponentially along with increase of external-cavity length is deduced from the composite cavity interference function. The attenuation coefficient is direct ratio to imaginary part of light frequency. A group of transcendental equations for imaginary part and real part of light frequency are also presented. By solving the equations, at external-cavity length more than a critical value, along with the increase of external-cavity length, the imaginary part is inversely proportional to attenuation, so the self-mixing interference signal attenuates very slowly. When external-cavity length is less than the critical value, feedback light increases the imaginary part, moreover, the imaginary part oscillates along with external-cavity length. The self-mixing interference signal appears as a complicated state. The greater the intensity of the external cavity feedback or the single-mode line-width of laser is, the smaller the critical value is. Analysis of the laser diode self-mixing interference also needs to consider the effect of feedback light on the imaginary part.

Kwok A.H.Y.,University of Hong Kong | Wang Y.,Sichuan University | Leung F.C.,University of Hong Kong
General and Comparative Endocrinology | Year: 2012

Prostaglandin E and F regulate diverse physiological functions including gastrointestinal motility, fever induction and reproduction. This multitude of biological effects is mediated via their four E receptor subtypes (EP1, EP2, EP3 and EP4) and F receptor (FP), respectively. Majority of these studies was performed in mammalian species, while investigations on their roles were impeded by inadequate information on their receptors in avian species. In present study, full-length cDNAs of chicken EP3 (cEP3) and two isoforms of FP - cFPa and cFPb - were cloned from adult hen ovary. The putative cEP3 and cFPa share high amino acid sequence identity with their respective orthologs, while the predicted cFPb is a novel middle-truncated splice variant which lacks 107 amino acids between transmembrane domains 4 and 6. RT-PCR showed that cEP3, cFPa and cFPb are widely expressed in adult tissues examined, including ovary and oviduct. Using a pGL3-CRE luciferase reporter system, cEP3-expressing DF1 cells inhibited forskolin-induced luciferase activity (EC50: <1.9pM) upon PGE2 treatment, suggesting that cEP3 may functionally couple to Gi protein. Upon PGF2α addition, cFPa was shown to potentially couple to intracellular Ca2+-signaling pathway by pGL3-NFAT-RE reporter assay (EC50: 2.9 nM), while cFPb showed no response. Using a pGL4-SRE reporter system, both cEP3 and cFPa exhibited potential MAPK activation by PGE2 and PGF2α at EC50 0.34 and 13nM, respectively. Molecular characterization of these receptors paved the road to the better understanding of PGE2 and PGF2α roles in avian physiology and comparative endocrinology studies. © 2012 Elsevier Inc.

Xia L.-W.,University of Sichuan | Xie R.,University of Sichuan | Ju X.-J.,University of Sichuan | Wang W.,University of Sichuan | And 4 more authors.
Nature Communications | Year: 2013

Smart hydrogels, or stimuli-responsive hydrogels, are three-dimensional networks composed of crosslinked hydrophilic polymer chains that are able to dramatically change their volume and other properties in response to environmental stimuli such as temperature, pH and certain chemicals. Rapid and significant response to environmental stimuli and high elasticity are critical for the versatility of such smart hydrogels. Here we report the synthesis of smart hydrogels which are rapidly responsive, highly swellable and stretchable, by constructing a nano-structured architecture with activated nanogels as nano-crosslinkers. The nano-structured smart hydrogels show very significant and rapid stimuli-responsive characteristics, as well as highly elastic properties to sustain high compressions, resist slicing and withstand high level of deformation, such as bending, twisting and extensive stretching. Because of the concurrent rapid and significant stimuli-response and high elasticity, these nano-structured smart hydrogels may expand the scope of hydrogel applications, and provide enhanced performance in their applications. © 2013 Macmillan Publishers Limited. All rights reserved.

Xu F.,Southwest Petroleum University | Yi Z.,Sichuan University
Computers and Mathematics with Applications | Year: 2011

A class of simplified background neural networks model with a large number of neurons is proposed. Continuous attractors of the simplified model are studied in this paper. It contains: (1) When the background inputs are set to zero and the excitatory connections are in Gaussian shape, continuous attractors of the new network are obtained under some condition. (2) When the background inputs are nonzero and the excitatory connections are still in Gaussian shape, continuous attractors are achieved under some appropriately selected condition. (3) Discussions and examples are used to illustrate the theories developed. © 2011 Elsevier Ltd. All rights reserved.

Hu X.-F.,Sichuan University
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2011

Signal waveforms of low frequency vibration of external cavity reflective surface were demodulated from self-mixing interference signals that external cavity length was modulated by a high frequency signal. In order to realize high frequency modulation of external cavity length against the low frequency vibration, a scheme of laser source sinusoidal vibration was proposed, in which a laser diode module was mounted on an electromagnetic vibrator with the length and diameter of 23 mm and 13 mm, respectively. The vibrator excited by a sinusoidal signal drives laser source vibration which amplitude and frequency was about a quarter wavelength and 7 kHz respectively. Using Fourier transform and phase unwrapped means, the low frequency vibration signal waveforms were demodulated from the self-mixing interference signals by digital signal process. The amplitude of the smallest waveform ably resolved was about 0.02 wavelengths. Light density or polarization direction of the laser source unchanged with modulation signal, which was superior to a phase modulator plugged in external cavity. From experimental measurement, it was sure that laser source of sinusoidal vibration can realize modulation of external cavity in self-mixing interference.

Tang X.,University of Sichuan | Tang X.,Sichuan University | Tang X.,Peking Union Medical College | Mo C.,University of Sichuan | And 3 more authors.
Immunology | Year: 2013

Tumour-associated macrophages (TAMs) represent a predominant population of inflammatory cells that present in solid tumours. TAMs are mostly characterized as alternatively activated M2-like macrophages and are known to orchestrate nearly all stages of tumour progression. Experimental investigations indicate that TAMs contribute to drug-resistance and radio-protective effects, and clinical evidence shows that an elevated number of TAMs and their M2 profile are correlated with therapy failure and poor prognosis in cancer patients. Recently, many studies on TAM-targeted strategies have made significant progress and some pilot works have achieved encouraging results. Among these, connections between some anti-tumour drugs and their influence on TAMs have been suggested. In this review, we will summarize recent advances in TAM-targeted strategies for tumour therapy. Based on the proposed mechanisms, those strategies are grouped into four categories: (i) inhibiting macrophage recruitment; (ii) suppressing TAM survival; (iii) enhancing M1-like tumoricidal activity of TAMs; (iv) blocking M2-like tumour-promoting activity of TAMs. It is desired that further attention be drawn to this research field and more effort be made to promote TAM-targeted tumour therapy. © 2012 Blackwell Publishing Ltd.

Peng D.,Sichuan University | Xiang Y.,Deakin University | Huang D.,University of Western Australia
IEEE Transactions on Signal Processing | Year: 2010

The complex exponential basis expansion model (CE-BEM) provides an accurate description for the time-varying (TV) channels encountered in mobile communications. Many blind channel identification and equalization approaches based on the CE-BEM require precise knowledge of the basis frequencies of TV channels. Existing methods for basis frequency estimation usually resort to the higher-order statistics of channel outputs and impose strict constraints on the source signal. In this paper, we propose a novel method to estimate the basis frequencies for blind identification and equalization of time-varying single-input multiple-output (SIMO) finite-impulse-response (FIR) channels. The proposed method exploits only the second-order statistics of channel outputs and does not require strong conditions on the source signal. As a result, it exhibits superior performance to the existing basis frequency estimation methods. The validity of our method is demonstrated by numerical simulations. © 2010 IEEE.

Jiang D.,Center for Nanotechnology | Jiang D.,Sichuan University | Seela F.,Center for Nanotechnology | Seela F.,University of Osnabruck
Journal of the American Chemical Society | Year: 2010

8-Aza-2′-deoxyisoguanosine (4) is the first fluorescent shape mimic of 2′-deoxyisoguanosine (1a); its fluorescence is stronger in alkaline medium than under neutral conditions. Nucleoside 4, which was synthesized from 8-aza-2′-deoxyguanosine via a 4,6-diamino intermediate after selective deamination, was incorporated in oligodeoxyribonucleotides using phosphoramidite 11. Duplexes with 4·m5iCd(5-methyl-2′- deoxyisocytidine) base pairs are more stable than those incorporating dG-dC pairs, thereby expanding the genetic alphabet by a fluorescent orthogonal base pair. As demonstrated by Tm measurements, the base pair stability decreases in the order m5iCd·4 dG·4 > dT·4 ≥ dC·4 dA·4. A better base pairing selectivity of 4 against the canonical nucleosides dT, dC, dA, and dG is observed than for the degenerated base pairing of 1a. The base pair stability changes can be monitored by nucleobase anion fluorescence sensing. The fluorescence change correlates to the DNA base pair stability. Oligonucleotide 5′-d(T44 4T4) (22), containing short runs of nucleoside 4, forms stable multistranded assemblies (ionophores) with K+ in the central cavity. They are quite stable at elevated temperature but are destroyed at high pH value. © 2010 American Chemical Society.

Poly(D,L-lactic acid)-co-poly(ethylene glycol) copolymer (D,L-PLEG) synthesized by melt polycondensation was irradiated using low energy electron beam (EB) in the presence of triallyl cyanurate (TAC) and tetraallyl pentaerythritol (TAPE) as crosslinking agents. The tensile strength of D,L-PLEG/TAC and D,L-PLEG/TAPE samples increases up to 48 MPa and 28 MPa at dose of 80 kGy and 60 kGy, respectively, and decreases with further increase of dose, whereas the elongation at break decreases continuously with increasing dose. The glass transition temperature (Tg) is improved to some extent due to the formation of molecular chain network. Degradation of D,L-PLEG is retarded with introduction of cross-linked network. The results suggest that the physical properties of crosslinked D,L-PLEG can be adjusted easily by varying irradiation dose.

Wu X.-X.,Civil Aviation Flight University of China | Zheng W.-C.,Sichuan University
Optik | Year: 2014

The thermal shifts of R1 and R2 lines of Cr 3+-doped garnets Y3Ga5O12 (YGG), Y3Sc2Al3O12 (YSAG) and Gd 3Sc2Al3O12 (GSAG) are studied by considering both the static contribution (which is frequently neglected in the previous papers) due to lattice thermal expansion and the vibrational contribution due to electron-phonon interaction. In the studies, the static contribution is calculated with the thermal expansion coefficient of the corresponding cluster in the host garnet crystals. The results indicate that the static contributions in sign are opposite to and in magnitude are about 10% of the corresponding vibrational contributions. The true electron-phonon coupling parameters α′ obtaining by taking both contributions into account increase more than 10% in comparison with the corresponding apparent electron-phonon coupling parameters α determined by considering only the vibrational contribution in the previous paper. So, to obtain the complete understanding of thermal shift of a spectral line and the true rather than apparent electron-phonon coupling parameters, one should take account of both the static and vibrational contributions. © 2014 Elsevier GmbH.

Fu H.Y.,Sichuan University | Chen L.,CNRS Chemistry Institute of Rennes | Doucet H.,CNRS Chemistry Institute of Rennes
Journal of Organic Chemistry | Year: 2012

Ligand-free Pd(OAc) 2 was found to catalyze very efficiently the direct arylation of imidazo[1,2-a]pyridines at C3 under very low catalyst concentration. The reaction can be performed employing as little as 0.1-0.01 mol % catalyst with electron-deficient and some electron-excessive aryl bromides. © 2012 American Chemical Society.

Fu H.,Sichuan University | Zhao L.,CNRS Chemistry Institute of Rennes | Bruneau C.,CNRS Chemistry Institute of Rennes | Doucet H.,CNRS Chemistry Institute of Rennes
Synlett | Year: 2012

Methyl 5-bromo-2-furoate and ethyl 5-bromothiophene-2-carboxylate have been found to be useful alternative reagents to 2-halofurans and 2-halothiophenes for the palladium-catalysed direct arylation of heteroaromatics. As their C5 is blocked by ester groups, the use of these substrates prevents the formation of dimers or oligomers, and therefore allows the formation of biheteroaryls in high yields. A very wide variety of heteroaromatics can be coupled with these two reagents. Moreover, with methyl 5-bromo-2-furoate, sequential catalytic C5 arylation, decarboxylation, catalytic C2-arylation reactions allowed the synthesis of 2,5-diarylated furan derivatives. © Georg Thieme Verlag Stuttgart New York.

Huang S.,Zhejiang University | Li C.,Zhejiang University | Liu Y.,Sichuan University
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

In this paper, we consider the training of complex-valued filter based on the information theoretic method. We first generalize the error entropy criterion to complex domain to present the complex error entropy criterion (CEEC). Due to the difficulty in estimating the entropy of complex-valued error directly, the entropy bound minimization (EBM) method is used to compute the upper bounds of the entropy of the complex-valued error, and the tightest bound selected by the EBM algorithm is used as the estimator of the complex-error entropy. Then, based on the minimization of complex-error entropy (MCEE) and the complex gradient descent approach, complex-valued learning algorithms for both the (linear) transverse filter and the (nonlinear) neural network are derived. The algorithms are applied to complex-valued linear filtering and complex-valued nonlinear channel equalization to demonstrate their effectiveness and advantages. © 2013 IEEE.

Mao H.,Sichuan Normal University | Mao H.,Nanyang Technological University | Yu H.,Nanyang Technological University | Chen J.,Nanyang Technological University | Liao X.,Sichuan University
Scientific Reports | Year: 2013

In the field of catalysis, it is highly desired to develop novel catalysts that combine the advantages of both homogeneous and heterogeneous catalysts. Here we disclose that the use of plant pholyphenol as amphiphilic large molecule ligand/stabilizer allows for the preparation of noble metal complex and noble metal nanoparticle catalysts. These catalysts are found to be highly selective and active in aqueous-organic biphasic catalysis of cinnamaldehyde and quinoline, and can be reused at least 3 times without significant loss of activity. Moreover, the catalytic activity and reusability of the catalysts can be rationally controlled by simply adjusting the content of polyphenols in the catalysts. Our strategy may be extended to design a wide range of aqueous-organic biphasic catalysis system.

Liu X.,Sichuan University | He B.,University of Electronic Science and Technology of China
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2011

Fuzzy C-means (FCM) algorithm has an equal partition trend for data sets. To overcome this disadvantage, several weighted FCM (WFCM) algorithms are formed by introducing the neighbor distributing characteristics of samples themselves in the standard FCM algorithm, they are neighbor sample density WFCM (NSD-WFCM), neighbor sample membership WFCM (NSM-WFCM) and neighbor sample density and membership WFCM (NSDM-WFCM). These algorithms are applied to a set of remote sensing images for classification. Classification results show that these WFCM algorithms (NSD-WFCM, NSM-WFCM and NSDM-WFCM) improve the classification accuracy of the FCM algorithm by 5.67%, 7.50% and 11.17%, and the Kappa coefficient by 8.50%, 11.25% and 16.75%, respectively. Experimental results indicate that these WFCM algorithms improve the clustering performance to some extent, and significantly improve the unsupervised classification ability of remote sensing images compared with the FCM algorithm; moreover, the classification performance of the NSM-WFCM algorithm is superior to that of the NSD-WFCM algorithm, and the NSDM-WFCM algorithm has the best classification performance in the three algorithms.

Tian Y.-H.,Sichuan University | Sumpter B.G.,Oak Ridge National Laboratory | Du S.,Ningbo Institute of Materials Technology and Engineering | Huang J.,Oak Ridge National Laboratory
Journal of Physical Chemistry Letters | Year: 2015

Chemical bonding interactions are the main driving force for the formation of molecules and materials from atoms. The two-electron/multicenter pancake π-π bonding found in phenalenyl (PLY, 1) radical π-dimers is intriguing due to its unconventional nature of covalent bonding for molecular aggregations and its propensity to induce unique optical, electronic, and magnetic properties. By using high-level quantum chemistry calculations, we show that the B- or N-doped PLYs (2 and 4), usually considered closed-shell and therefore trifling, can be rendered open-shell singlet by proper edge substitutions (3 and 5). The resulting two unpaired valence electrons on each molecular unit contribute to the formation of a genuine pancake-shaped 4e/all-sites double π-π bonding upon intermolecular π-dimerization, in contrast to the 2e/half-sites single π-π bonding in the parent PLY π-dimers. The unusual double π-π bonding motif discovered in these PLY analogues may broaden the landscape of, and find new applications for, intermolecular covalent bonding interactions. © 2015 American Chemical Society.

Ho S.-S.,Nanyang Technological University | Ruan S.,Sichuan University
Transactions on Data Privacy | Year: 2013

One main concern for individuals participating in the data collection of personal location history records (i.e., trajectories) is the disclosure of their location and related information when a user queries for statistical or pattern mining results such as frequent locations derived from these records. In this paper, we investigate how one can achieve the privacy goal that the inclusion of his location history in a statistical database with interesting location mining capability does not substantially increase risk to his privacy. In particular, we propose a (∈, δ)-differentially private interesting geographic location pattern mining approach motivated by the sample-aggregate framework. The approach uses spatial decomposition to limit the number of stay points within a localized spatial partition and then followed by density-based clustering. The (∈, δ)-differential privacy mechanism is based on translation and scaling insensitive Laplace noise distribution modulated by database instance dependent smoothed local sensitivity. Unlike the database independent ∈-differential privacy mechanism, the output perturbation from a (∈, δ)-differential privacy mechanism depends on a lower (local) sensitivity resulting in a better query output accuracy and hence, more useful at a higher privacy level, i.e., smaller ∈. We demonstrate our (∈, δ)-differentially private interesting geographic location discovery approach using the region quadtree spatial decomposition followed by the DBSCAN clustering. Experimental results on the real-world GeoLife dataset are used to show the feasibility of the proposed (∈, δ)-differentially private interesting location mining approach.

Here and in the companion paper, the physical performance measurement, especially measurement units and physical dimensions of fractance and rules for fractors in series and parallel are discussed. The concept of fractance, as the fractional-order impedance of a fractor, arose following the successful synthesis of a fractional differentiator in an analogue circuit. Until now, however, the measurement units and physical dimensions of fractance have not been proposed. Motivated by this need, in this paper, I studied the electrical properties of fractor. In particular, the driving-point impedance function of the arbitrary-order fractor in its natural implementation is introduced. Through mathematical and physical analysis, the driving-point impedance function of the 1/2-order fractor is studied, following which the driving-point impedance function of the arbitrary-order fractor is proposed. This paper discusses fundamental issues, whereas Part II is devoted to the measurement units and physical dimensions of fractance and the rules for fractors in series and parallel. © 2015 W. S. Maney & Son Ltd.

Up to now, no effective physical performance measurements have been proposed for fractor, a promising circuit element, especially with regard to the measurement units and physical dimensions of fractance. Motivated by this need, in this paper, I study the physical performance measurement of fractor. In particular, the fundamental issues introduced in the companion paper (Part I) are combined with a proposal for the measurement units and physical dimensions of fractance, together with the rules for fractors in series and parallel, respectively. Through mathematical and physical analysis, I first propose the measurement units (Yi-Fei PU)-V and (Yi-Fei PU)V, for capacitive fractance and inductive fractance, respectively, as well as the physical dimensions of fractance. I then introduce the rules for fractors in series and parallel. © 2015 W. S. Maney & Son Ltd.

Liu J.,Hefei University of Technology | Sui Y.,Hefei University of Technology | Wisniewski M.,U.S. Department of Agriculture | Droby S.,Israel Agricultural Research Organization | And 2 more authors.
International Journal of Food Microbiology | Year: 2013

Significant losses in harvested fruit can be directly attributable to decay fungi. Some of these pathogenic fungi are also the source of mycotoxins that are harmful to humans. Biological control of postharvest decay of fruits, vegetables and grains using antagonistic yeasts has been explored as one of several promising alternatives to chemical fungicides, the use of which is facing increasingly more stringent regulation. Yeast species have been isolated over the past two decades from a variety of sources, including fruit surfaces, the phyllosphere, soil and sea water, and their potential as postharvest biocontrol agents has been investigated. Several mechanisms have been proposed as responsible for their antagonistic activity, including competition for nutrients and space, parasitism of the pathogen, secretion of antifungal compounds, induction of host resistance, biofilm formation, and most recently, the involvement of reactive oxygen species (ROS) in defense response. It has been recognized that a biocontrol system is composed of a three-way interaction between the host (commodity), the pathogen and the yeast, all of which are affected by environmental factors. Efficacy and consistent performance in controlling postharvest diseases are the hurdles that must be overcome if the use of yeast biocontrol agents and other alternatives are to be widely used commercially. Therefore, attempts have been made to combine alternative treatments in order improve their overall performance. The current review provides a brief overview of the topic of the use of yeasts as postharvest biocontrol agents and includes information on the sources from which yeast antagonists have been isolated, their mode of action, and abiotic stress resistance in yeast as it relates to biocontrol performance. Areas in need of future research are also highlighted. © 2013 Elsevier B.V.

Ho S.-S.,University of Maryland University College | Ruan S.,Sichuan University
SPRINGL 2011 - Proceedings of the 4th ACM SIGSPATIAL International Workshop on Security and Privacy in GIS and LBS | Year: 2011

One main concern for individuals to participate in the data collection of personal location history records is the disclosure of their location and related information when a user queries for statistical or pattern mining results derived from these records. In this paper, we investigate how the privacy goal that the inclusion of one's location history in a statistical database with location pattern mining capabilities does not substantially increase one's privacy risk. In particular, we propose a differentially private pattern mining algorithm for interesting geographic location discovery using a region quadtree spatial decomposition to preprocess the location points followed by applying a density-based clustering algorithm. A differentially private region quadtree is used for both de-noising the spatial domain and identifying the likely geographic regions containing the interesting locations. Then, a differential privacy mechanism is applied to the algorithm outputs, namely: the interesting regions and their corresponding stay point counts. The quadtree spatial decomposition enables one to obtain a localized reduced sensitivity to achieve the differential privacy goal and accurate outputs. Experimental results on synthetic datasets are used to show the feasibility of the proposed privacy preserving location pattern mining algorithm. © 2011 ACM.

Zheng J.,Sichuan University
Journal of Computational and Theoretical Nanoscience | Year: 2016

Let G = (V,E) be a graph. For two vertices u and v in G, we denote d(u, v) the distance between u and v. An L(2, 1, 1)-labeling for G is a function f: V →0, 1,.) such that for any two vertices u and v,f (u).f (v), ≥ 2 if d(u, v) = 1 and,f (u)≥f (v), ≥ 1 if d(u, v) = 2 and,f (u).f (v), ≥ 1 if d(u, v) = 3. The span of f is the difference between the largest and the smallest numbers in f (V). The 2, 1, 1-number for G is the minimum span over all L(2, 1, 1)-labelings of G. In this paper, an ILP model was used to study the L(2, 1, 1)-labeling problem of some strong product of paths and cycles. Based on this method, we succeed to determine the λ2, 1, 1-numbers of all the strong product of two paths as well as some strong product of two cycles. © 2016 American Scientific Publishers All rights reserved.

Ding J.,CAS Institute of Biophysics | Bao J.,Sichuan University | Zhu D.,Shandong University | Zhang Y.,CAS Institute of Biophysics | Wang D.-C.,CAS Institute of Biophysics
Journal of Structural Biology | Year: 2010

Polygonatum cyrtonema lectin (PCL) is a novel anti-HIV mannose-binding lectin from Galanthus nivalis agglutinin (GNA)-related lectin family. Crystal structures of ligand-free PCL and its complexes with monomannoside and α1-3 dimannoside have been determined. The ligand-free PCL is dimeric, with both subunits adopt the β-prism II fold. PCL subunit binds mannose using a potential bivalent mode instead of the usual trivalent mode, in which carbohydrate-binding site (CBS) I and CBS III adopt the conserved mannose-binding motif of QXDXNXVXY (X is one of any amino acid residues) as observed in other structurally characterized GNA-related lectins, while CBS II adopts a modified motif with residues Gln58 and Asp60, which are critical for mannose-binding, substituted by His58 and Asn60, respectively. As a result, CBS II is unfit for mannose-binding. In the mannoside complexes, ligand-bindings only occur at CBS I which provides the specificity for α1-3 dimannoside. CBS II and CBS III are cooperatively occupied by a well-ordered sulfate ion, through which the individual dimers are cross-linked to form a unique super-structure of 32 helical lattice. Surveying the sequences of GNA-related lectins revealed that the modified binding motif of CBS II is widely distributed in the Liliaceae family as an intrinsic structural element. There is evidence that other GNA-related lectins will also adopt the similar super-structure as PCL. Thus PCL structure, unique in ligand-binding mode, may represent a novel type of structure of GNA-related lectins. Comparative analyses indicated that the dimer-based super-structure may play a primary role in the anti-HIV property of PCL. © 2010 Elsevier Inc.

Zheng J.,Sichuan University
Journal of Computational and Theoretical Nanoscience | Year: 2016

Motivated with the radio channel assignment problem, Chartrand et al. initiated the study of radio k-labelings of graphs. A radio k-labeling of a graph G is an assignment f of non-negative integers to the vertices of G such that (f (x)-f (y)(= k +1-d(x,y), for any two vertices x and y, x,= y, where d(x,y) is the distance between x and y in G. The span of the function f denoted by r lk (f), is max f (x)-f (y)≥ x,y. V (G). The radio k-labeling number r lk(G) of G is the minimum span among all radio k-labelings of G. A radio (resp. antipodal) k-labeling with k = diam(G) (resp. k = diam(G)-1) is known as a radio (resp. antipodal) labeling, where diam(G) is the diameter of the graph G. The minimum span of a radio (resp. antipodal) labeling is called the radio (resp. antipodal) number, denoted by rn(G) (resp. an(G)). In this paper, we determine all the radio numbers and antipodal numbers of trees with order up to eight. © 2016 American Scientific Publishers All rights reserved.

Wang W.,University of Sichuan | Zhang M.-J.,University of Sichuan | Chu L.-Y.,University of Sichuan | Chu L.-Y.,Sichuan University
Current Opinion in Pharmacology | Year: 2014

Double emulsions, with inner drops well protected by the outer shells, show great potential as compartmentalized systems to encapsulate multiple components for protecting actives, masking flavor, and targetedly delivering and controllably releasing drugs. Precise control of the encapsulation characteristics of each component is critical to achieve an optimal therapeutic efficacy for pharmaceutical applications. Such controllable encapsulation can be realized by using microfluidic approaches for producing monodisperse double emulsions with versatile and controllable structures as the encapsulation system. The size, number and composition of the emulsion drops can be accurately manipulated for optimizing the encapsulation of each component for pharmaceutical applications. In this review, we highlight the outstanding advantages of controllable microfluidic double emulsions for highly efficient and precisely controllable encapsulation. © 2014 Elsevier Ltd. All rights reserved.

Wu X.-X.,Civil Aviation Flight University of China | Zheng W.-C.,Sichuan University
Zeitschrift fur Naturforschung - Section A Journal of Physical Sciences | Year: 2014

The thermal shifts of R1 and R2 lines in Cr3+-doped forsterite (Mg2SiO4) are studied by considering both the static contribution due to lattice thermal expansion and the vibrational contribution due to electron-phonon interaction. In the studies, the thermal expansion coefficient of the Cr3+ center is assumed reasonably as that of the corresponding cluster in the host crystal. The results suggest that for R1 and R2 lines the static contributions are opposite in sign and in magnitude about 37% and 45%, respectively, of the corresponding vibrational contributions. The true electron-phonon coupling coefficients α' (obtained by considering both contributions) increase by about 58% and 81%, respectively, for R1 and R2 lines in comparison with the corresponding parameters a obtained by considering only the vibrational contribution. It appears that for the reasonable explanation of thermal shift of spectral lines and the exact estimation of electron-phonon coupling coefficient, both the static and vibrational contributions should be taken into account. © 2014 Verlag der Zeitschrift für Naturforschung, Tübingen.

Deng N.-N.,University of Sichuan | Wang W.,University of Sichuan | Ju X.-J.,University of Sichuan | Xie R.,University of Sichuan | And 3 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2013

Multiple emulsions, which are widely applied in a myriad of fields because of their unique ability to encapsulate and protect active ingredients, are typically produced by sequential drop-formations and drop-encapsulations using shear-induced emulsification. Here we report a qualitatively novel method of creating highly controlled multiple emulsions from lower-order emulsions. By carefully controlling the interfacial energies, we adjust the spreading coefficients between different phases to cause drops of one fluid to completely engulf other drops of immiscible fluids; as a result multiple emulsions are directly formed by simply putting preformed lower-order emulsion drops together. Our approach has highly controllable flexibility. We demonstrate this in preparation of both double and triple emulsions with a controlled number of inner drops and precisely adjusted shell thicknesses including ultra-thin shells. Moreover, this controllable drop-engulfing-drop approach has a high potential in further investigations and applications of microfluidics. Importantly, this innovative approach opens a window to exploit new phenomena occurring in fluids at the microscale level, which is of great significance for developing novel microfluidics. © The Royal Society of Chemistry 2013.

Huang X.,University of Kentucky | Liu J.,University of Kentucky | Liu J.,Sichuan University | Withers B.R.,University of Kentucky | And 3 more authors.
Aging Cell | Year: 2013

Disease incidence rises rapidly with age and increases both human suffering and economic hardship while shortening life. Advances in understanding the signaling pathways and cellular processes that influence aging support the possibility of reducing the incidence of age-related diseases and increasing lifespan by pharmacological intervention. Here, we demonstrate a novel pharmacological strategy that both reduces signs of aging in the budding yeast Saccharomyces cerevisiae and generates a synergistic increase in lifespan. By combining a low dose of rapamycin, to reduce activity of the target of rapamycin complex 1 (TORC1) protein kinase, and myriocin, to reduce sphingolipid synthesis, we show enhancement of autophagy, genomic stability, mitochondrial function, and AMP kinase pathway activity. These processes are controlled by evolutionarily conserved signal transduction pathways that are vital for maintaining a healthy state and promoting a long life. Thus, our data show that it ought to be possible to find pharmacological approaches to generate a synergistic reduction in the incidence of human age-related diseases to improve health quality in the elderly and enhance lifespan. © 2013 John Wiley & Sons Ltd and the Anatomical Society.

Miyamoto Y.,Japan National Institute of Advanced Industrial Science and Technology | Zhang H.,Sichuan University | Miyazaki T.,Japan National Institute of Advanced Industrial Science and Technology | Rubio A.,Max Planck Institute for the Structure and Dynamics of Matter | Rubio A.,University of the Basque Country
Physical Review Letters | Year: 2015

We propose a transient interlayer compression in two-dimensional compound materials by using an intense IR laser resonant with the out-of-plane optical phonon mode (A2u mode). As a test case, we studied bilayer hexagonal boron nitride (h-BN), which is one of the compound layered materials. Excited state molecular dynamics calculations using time-dependent density functional theory show an 11.3% transient interlayer contraction of h-BN due to an interlayer dipole-dipole attraction of the laser-pumped A2u mode. These results are applicable to other layered compound materials. Such layered materials are a good material for nanospace chemistry, e.g., intercalating molecules and acting with them, and IR irradiation to contract the interlayer distance could provide a new route for chemical reactions under pressure. The duration of the contraction is at least 1 ps in the current simulation, which is observable by high-speed electron-beam diffraction measurements. © 2015 American Physical Society.

Xie F.,Sichuan University
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2010

OBJECTIVE: New wild strains, which were endowed with an effective depilation as their abilities to produce keratinase, were isolated to develop the bio-deliplatory agent in the sulfur-free tanning. METHODS: A polyphase screening method was used to obtain the high-yielding wild strains. In this method, the sewage sample was obtained from the specific circumstance where the raw hides were stored,and then enriched by adding the defatted wool power as an inducer in the medium. Furthermore,the strains were screened via assessing the ability of the depilation of their fermentation broth. Finally, the isolated strain was identified according to their morphological features, physiological and biochemical characteristics, automatic identification by Biolog system as well as phylogenetic analysis of 16SrDNA sequences. RESULTS: A higher activity and remarkable dehairing capability with sulfur-free was obtained. The results of identification indicated that the strain X-47 was the most closely related to Bacillus licheniformis, so it was named Bacillus licheniformis X-47. CONCLUSION: The wild strain Bacillus licheniformis X-47 was isolated successfully by the method of polyphase screening. It had a high keratinase-producing activity, high efficient of depilation and weak effect on collagen, which suggested that it has a considerable potential of developing the sulfur-free bio-depilation product.

Xiang Y.,Deakin University | Peng D.,Sichuan University | Guo S.,University of Aizu
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

In this paper, we address the problem of blind separation of spatially correlated signals, which is encountered in some emerging applications, e.g., distributed wireless sensor networks and wireless surveillance systems. We preprocess the source signals in transmitters prior to transmission. Specifically, the source signals are first filtered by a set of properly designed precoders and then the coded signals are transmitted. On the receiving side, the Z-domain features of the precoders are exploited to separate the coded signals, from which the source signals are recovered. Based on the proposed precoders, a closed-form algorithm is derived to estimate the coded signals and the source signals. Unlike traditional blind source separation approaches, the proposed method does not require the source signals to be uncorrelated, sparse, or nonnegative. Compared with the existing precoder-based approach, the new method uses precoders with much lower order, which reduces the delay in data transmission and is easier to implement in practice. © 2012 IEEE.

Zhang T.,Zhengzhou University | Chu J.,Zhengzhou University | Zhou X.,Sichuan University
Phytotherapy Research | Year: 2015

As a natural traditional Chinese medicine, Galla chinensis has been widely used since ancient times for its astringency, stypticity, detoxification, and antibacterial activity. Our group has concentrated on the research about its potential of being an applicable anti-caries agent. The crude extract and some other components purified from it show remarkable efficacy on anticaries, and the most likely mechanism is proposed through specific research. For the fact that crude drugs consist of numerous compounds, and their bioactivity is a result of synergistic effects and/or antagonistic effects of several compounds, it is difficult to clarify the exact mechanism and evaluate the safety and effectiveness of G. chinensis. This review article systematically summarizes previous findings from the following aspects: (1) inhibitory effect on oral bacteria; (2) the demineralization inhibition property; (3) the remineralization-enhancing property; and (4) stability and toxicity evaluation, and thus indicates the further research direction. Copyright © 2015 John Wiley & Sons, Ltd.

Wei X.-Y.,City University of Hong Kong | Jiang Y.-G.,Sichuan University | Ngo C.-W.,Columbia University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2011

As it is true for human perception that we gather information from different sources in natural and multi-modality forms, learning from multi-modalities has become an effective scheme for various information retrieval problems. In this paper, we propose a novel multi-modality fusion approach for video search, where the search modalities are derived from a diverse set of knowledge sources, such as text transcript from speech recognition, low-level visual features from video frames, and high-level semantic visual concepts from supervised learning. Since the effectiveness of each search modality greatly depends on specific user queries, prompt determination of the importance of a modality to a user query is a critical issue in multi-modality search. Our proposed approach, named concept-driven multi-modality fusion (CDMF), explores a large set of predefined semantic concepts for computing multi-modality fusion weights in a novel way. Specifically, in CDMF, we decompose the query-modality relationship into two components that are much easier to compute: query-concept relatedness and concept-modality relevancy. The former can be efficiently estimated online using semantic and visual mapping techniques, while the latter can be computed offline based on concept detection accuracy of each modality. Such a decomposition facilitates the need of adaptive learning of fusion weights for each user query on-the-fly, in contrast to the existing approaches which mostly adopted predefined query classes and/or modality weights. Experimental results on TREC video-retrieval evaluation 20052008 dataset validate the effectiveness of our approach, which outperforms the existing multi-modality fusion methods and achieves near-optimal performance (from oracle fusion) for many test queries. © 2011 IEEE.

Li C.,Chengdu University of Technology | Miao X.,Chengdu University of Technology | Chu W.,Sichuan University | Wu P.,Chengdu University of Technology | Tong D.G.,Chengdu University of Technology
Journal of Materials Chemistry A | Year: 2015

Hollow amorphous NaFePO4 nanospheres were prepared on a large scale by a simple in situ hard template process, wherein the hollow nanospheres exhibited a high storage capacity and high rate as a cathode material for sodium-ion batteries. © The Royal Society of Chemistry 2015.

Mei Y.,Mianyang Normal University | Mei Y.,CAEP - China Academy of Engineering Physics | Zheng W.-C.,Sichuan University
Journal of Magnetism and Magnetic Materials | Year: 2013

The spin-Hamiltonian parameters (g factors g∥, g ⊥ and hyperfine structure constants A∥, A ⊥) of the tetragonal Mo5+ center in reduced BaTiO3:Mo crystal with low temperature phase are calculated from the high-order perturbation formulas based on the two-mechanism model for d 1 ions in octahedral clusters with the ground state 2B2 (|dxy〉). In the model, both the contributions to spin-Hamiltonian parameters from the crystal-field (CF) mechanism and that from the charge-transfer (CT) mechanism (which is neglected in the widely-used crystal field theory) are considered. The calculated results are in reasonably agreement with the experimental values. The calculations show that for the spin-Hamiltonian parameters of BaTiO3:Mo5+, the relative importances of CT mechanism |QCT/QCF| are about 17%, 9%, 7% and 7% for Q=Δg∥, Δg ⊥, A∥(2), and A⊥(2) (where Δg=g-ge, ge≈2.0023, the g factor of free electron), respectively. It appears that for the high valence state dn ion clusters in crystals, the precise and complete calculations of spin-Hamiltonian parameters should take both the CF and CT mechanisms into account. The tetragonally-compressed distortion of (MoO6)7- octahedral clusters in the low-temperature rhombohedral phase of BaTiO3 caused by the static Jahn-Teller effect is also acquired from the calculations. The results are discussed. © 2013 Elsevier B.V.

Xu J.,Beijing Computational Science Research Center | Xu J.,Sichuan University
Journal of Physics A: Mathematical and Theoretical | Year: 2012

Geometric quantum discord, proposed by Dakic et al (2010 Phys. Rev. Lett. 105 190502), is an important measure for bipartite correlations. In this paper, we generalize it to multipartite states, we call the generalized version geometric global quantum discord (GGQD). We characterize GGQD in different ways, give a lower bound for GGQD and provide some special states which allow analytical GGQD. © 2012 IOP Publishing Ltd.

We have derived the analytical expression of the electric cross-spectral density in the near- field of partially coherent vortex beams diffracted by an aperture. Taking the Gaussian Schell-model vortex beam as a typical example of partially coherent vortex beams, the spatial correlation properties and correlation vortices in the near-field of partially coherent vortex beams diffracted by a rectangle aperture are studied. It is shown that the off-axis displacement, spatial degree of coherence parameter, propagation distance, and the opening factor of the aperture affect the spectral degree of coherence and positions of correlation vortices. With the optimization algorithm, we obtain the symmetric distributing coherent vortex. © 2010 Chinese Physical Society and IOP Publishing Ltd.

Zhou Z.,Sichuan University
International Journal of Distributed Sensor Networks | Year: 2015

Walking while staring at the mobile phone is dangerous, and the danger mainly arises from distraction. While watching the mobile phone, one could fall into a deep well without noticing the manhole cover was missing, one could be hit by a rushing car without observing the traffic light, and so forth. Some mobile phone users are already aware of the crisis, and they keep looking up and down to allocate some focus to danger spying; however, the statistics data revealed by US government make such efforts frustrating: about 1,152 pedestrians are injured in US in the year 2010, while they were using mobile phones, and the number doubled in the year 2012. This paper identified the possibility of using mobile phone sensors to develop a walk pattern recognition system. By sampling from embedded sensor, such as accelerometer and gyroscope, the movement pattern of mobile phone users can be computed. We design and implement HeadsUp, a system that warns pedestrian and locks the screen when one looks at the mobile phone while walking. Evaluation results from experiments of 20 testers in real life situation show that, on average, the false negative rate is less than 3%. © 2015 Zhengjuan Zhou.

Polarization singularities in the near-field of Gaussian vortex beams diffracted by a circular aperture are studied by a rigorous electromagnetic theory. It is shown that there exist C-points and L-lines, which depend on off-axis displacement parameters along the x and y directions, waist width, wavelength, and topological charge of the diffracted Gaussian vortex beam, as well as on propagation distance. The results are illustrated by numerical calculations. © 2010 Chinese Physical Society and IOP Publishing Ltd.

Tang D.,Design Science | Hu C.,Sichuan University
Journal of Physical Chemistry Letters | Year: 2011

All-electron relativistic density functional theory (DFT) calculations on CO oxidation catalyzed by 55-atom gold nanoclusters (Au55) have revealed that all of neutral, anionic, and cationic Au55 clusters exhibit stronger catalytic efficiency toward CO oxidation at low temperatures. High spin energy profiles and spin crossing play a noticeably important role in CO oxidation catalyzed by gold nanoclusters. Our findings provide new insight into the charge and spin-state effects of gold nanoclusters within gold nanocatalysts. © 2011 American Chemical Society.

Faustman C.,University of Connecticut | Sun Q.,Sichuan University | Mancini R.,University of Connecticut