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Tianjin, China

Nankai University , often known as Nankai, is a public research university located in Tianjin mainland China. Founded in 1919 by prominent educators Zhang Boling and Yan Fansun , Nankai is one of the most prestigious universities in China. Its alumi include the former Premier Zhou Enlai and Nobel laureates Chen Ning Yang and Tsung-Dao Lee. Wikipedia.

Feng Z.,Rti International | Liu C.,Brown University | Guan X.,Nankai University | Mor V.,Brown University
Health Affairs | Year: 2012

In China, formal long-term care services for the large aging population have increased to meet escalating demands as demographic shifts and socioeconomic changes have eroded traditional elder care. We analyze China's evolving long-term care landscape and trace major government policies and private-sector initiatives shaping it. Although home and community-based services remain spotty, institutional care is booming with little regulatory oversight. Chinese policy makers face mounting challenges overseeing the rapidly growing residential care sector, given the tension arising from policy inducements to further institutional growth, a weak regulatory framework, and the lack of enforcement capacity.We recommend addressing the following pressing policy issues: building a balanced system of services and avoiding an "institutional bias" that promotes rapid growth of elder care institutions over home or community-based care; strengthening regulatory oversight and quality assurance with information systems; and prioritizing education and training initiatives to grow a professionalized long-term care workforce. © 2012 Project HOPE- The People-to-People Health Foundation, Inc.

Xiang D.,CAS Beijing National Laboratory for Molecular | Xiang D.,Nankai University | Wang X.,CAS Beijing National Laboratory for Molecular | Jia C.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Chemical Reviews | Year: 2016

Creating functional electrical circuits using individual or ensemble molecules, often termed as "molecular-scale electronics", not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlight the major contributions and new concepts of integrating molecular functionalities into electrical circuits. Finally, we provide a critical discussion of limitations and main challenges that still exist for the development of molecular electronics. These analyses should be valuable for deeply understanding charge transport through molecular junctions, the device fabrication process, and the roadmap for future practical molecular electronics. © 2016 American Chemical Society.

Wu Z.,Nankai University | Ge S.,Petrochina
Catalysis Communications | Year: 2011

A Co-B nanoparticle catalyst was prepared by a modified polyol method. Borohydride served both as a reducing agent for Co2+ and as a boron source, and the solvent, ethylene glycol, served as the surfactant and stabilizer to assemble Co-B clusters into small and uniform particles. The as-prepared Co-B possessed high surface active metal area and highly unsaturated coordinated Co metal, resulting in lower activation energy and higher hydrogen generation rate for hydrolysis of alkaline NaBH4 solution than the conventional Co-B catalyst synthesized from chemical reduction in water bath. © 2011 Elsevier B.V. All rights reserved.

This article aims to analyze and visualize the structure and the emerging trend of digital medicine, a new medical pattern of twenty-first century. Our study objectively explores the document co-citation clusters of 6060 bibliographic records to identify the origin of digital medicine and the hot research specialty of domain. Pivotal point articles, prominent authors, active disciplines and institution have been identified by network analysis theory. CiteSpace was used to visualize the perspective of digital medicine domain. As an interdiscipline which integrated computer science, information engineering with medicine, digital medicine originally and mainly on digital medical imaging technology research for accuracy and speedy clinical diagnosis and therapy. Of 6060 relevant records reviewed, 1719 (28 %) are on radiology, 902 (15 %) are on engineering, 539 (9 %) are on computer science. The largest co-citation cluster is on digital tomosynthesis. The earliest cluster is on medical imaging segmentation and registration. Post-processing imaging technology, detector, phase contrast, reversible watermarking, input, model 3D reconstruct, real-time dynamic imaging, dosimetry have been the hot research topics. The recently cluster is on internet health information. Harvard University of USA is the prominent institution. The coverage of digital medicine research is widely from clinic to laboratory. Recent year, domain research front is thematically on teleradiology, telemedicine and hospital information management system. © 2015 Akadémiai Kiadó, Budapest, Hungary

Wang W.,North China Electrical Power University | Han Z.-L.,Nankai University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

In this paper we propose a radiated linear seesaw model where the naturally small term μL is generated at the one-loop level and its soft breaking of lepton number symmetry contributes to the spontaneous breaking (SSB) of B-L gauge symmetry. The value of B-L charges for new particles are assigned to satisfy the cancellation of anomalies. It is found that some new particles may have exotic values of B-L charge such that there exists residual Z2×Z2′ symmetry even after SSB of B-L gauge symmetry. The Z2×Z2′ discrete symmetry stabilizes these particles as dark matter candidates. In the model, two classes of inert fermions and scalars with different B-L charges are introduced, leading to two-component dark matter candidates. The lepton-flavor-violation processes, the relic density of dark matter, the direct detection of dark matter and the phenomenology at the LHC are investigated. © 2015 American Physical Society.

Zhang X.-X.,Nankai University | Zhang X.-X.,Humboldt University of Berlin | Liang M.,Pennsylvania State University | Ernsting N.P.,Humboldt University of Berlin | Maroncelli M.,Pennsylvania State University
Journal of Physical Chemistry Letters | Year: 2013

It was shown recently that a simple dielectric continuum model predicts the integral solvation time of a dipolar solute âŸ̈τ solv⟩ to be inversely proportional to the electrical conductivity σ0 of an ionic solvent or solution. In this Letter, we provide a more general derivation of this connection and show that available data on coumarin 153 (C153) in ionic liquids generally support this prediction. The relationship between solvation time and conductivity can be expressed by ln(âŸ̈τsolv⟩/ps) = 4.37 - 0.92 ln (σ0/S m-1) in 34 common ionic liquids. © 2013 American Chemical Society.

MicroRNAs (miRNAs) are a class of small endogenous, non-coding RNAs that have key regulatory functions in plant growth, development, and other biological processes. Hypocotyl and cotyledon are the two major tissues of cauliflower (Brassica oleracea L. var. botrytis) seedlings. Tissue culture experiments have indicated that the regenerative abilities of these two tissues are significantly different. However, the characterization of miRNAs and their roles in regulating organ development in cauliflower remain unexplored. In the present study, two small RNA libraries were sequenced by Solexa sequencing technology. 99 known miRNAs belonging to 28 miRNA families were identified, in which 6 miRNA families were detected only in Brassicaceae. A total of 162 new miRNA sequences with single nucleotide substitutions corresponding to the known miRNAs, and 32 potentially novel miRNAs were also first discovered. Comparative analysis indicated that 42 of 99 known miRNAs and 17 of 32 novel miRNAs exhibited significantly differential expression between hypocotyl and cotyledon, and the differential expression of several miRNAs was further validated by stem-loop RT-PCR. In addition, 235 targets for 89 known miRNAs and 198 targets for 24 novel miRNAs were predicted, and their functions were further discussed. The expression patterns of several representative targets were also confirmed by qRT-PCR analysis. The results identified that the transcriptional expression patterns of miRNAs were negatively correlated with their targets. These findings gave new insights into the characteristics of miRNAs in cauliflower, and provided important clues to elucidate the roles of miRNAs in the tissue differentiation and development of cauliflower.

Kong X.,Nankai University | Huang Y.,Center for Nanoscale Science and Technology
Journal of Nanoscience and Nanotechnology | Year: 2014

This paper reviews the up-to-date research about the applications of graphene and its related materials in the field of mass spectrometry (MS). Due to its large surface area, delocalized π-electrons, thermal conductivity, stability and rich interaction chemistry, graphene has been widely used in MS-based analytical chemistry. Graphene-based materials were applied as very effective matrixes or surfaces for many kinds of organic molecules in laser desorption/ionization (LDI) MS analysis. Many advantages of this novel matrix have been proved, which included: low interference ions from matrix itself, good reproducibility, high salt tolerance and so on. The unique properties of graphene also make it a superior sorbent used in solid-phase extraction (SPE). Further development of online SPE methods based on graphene coupling directly with LDI-MS, GC-MS and LC-MS greatly simplifies the MS-based analytical procedure for complex samples and makes the corresponding high-throughput and automatic analysis performable. Their applications as a platform in proteolysis for the rapid identification of proteins have been also developed. In addition, graphene was found to be a unique precursor for the generation of large-sized carbon cluster anions in the gas phase. Finally, the possible challenges and future perspectives in their applications in MS are discussed too. Copyright © 2014 American Scientific Publishers All rights reserved.

Wang Z.,Nankai University | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Strategy changes are an essential part of evolutionary games. Here, we introduce a simple rule that, depending on the value of a single parameter w, influences the selection of players that are considered as potential sources of the new strategy. For positive w players with high payoffs will be considered more likely, while for negative w the opposite holds. Setting w equal to zero returns the frequently adopted random selection of the opponent. We find that increasing the probability of adopting the strategy from the fittest player within reach, i.e., setting w positive, promotes the evolution of cooperation. The robustness of this observation is tested against different levels of uncertainty in the strategy adoption process and for different interaction networks. Since the evolution to widespread defection is tightly associated with cooperators having a lower fitness than defectors, the fact that positive values of w facilitate cooperation is quite surprising. We show that the results can be explained by means of a negative feedback effect that increases the vulnerability of defectors although initially increasing their survivability. Moreover, we demonstrate that the introduction of w effectively alters the interaction network and thus also the impact of uncertainty by strategy adoptions on the evolution of cooperation. © 2010 The American Physical Society.

Cheng M.-M.,Nankai University | Mitra N.J.,University College London | Huang X.,Lehigh University | Torr P.H.S.,University of Oxford | Hu S.-M.,Tsinghua University
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2015

Automatic estimation of salient object regions across images, without any prior assumption or knowledge of the contents of the corresponding scenes, enhances many computer vision and computer graphics applications. We introduce a regional contrast based salient object detection algorithm, which simultaneously evaluates global contrast differences and spatial weighted coherence scores. The proposed algorithm is simple, efficient, naturally multi-scale, and produces full-resolution, high-quality saliency maps. These saliency maps are further used to initialize a novel iterative version of GrabCut, namely SaliencyCut, for high quality unsupervised salient object segmentation. We extensively evaluated our algorithm using traditional salient object detection datasets, as well as a more challenging Internet image dataset. Our experimental results demonstrate that our algorithm consistently outperforms 15 existing salient object detection and segmentation methods, yielding higher precision and better recall rates. We also show that our algorithm can be used to efficiently extract salient object masks from Internet images, enabling effective sketch-based image retrieval (SBIR) via simple shape comparisons. Despite such noisy internet images, where the saliency regions are ambiguous, our saliency guided image retrieval achieves a superior retrieval rate compared with state-of-the-art SBIR methods, and additionally provides important target object region information. © 2014 IEEE.

Zhang T.,Nankai University
Nature Photonics | Year: 2015

It has been a great challenge to achieve the direct light manipulation of matter on a bulk scale. In this work the direct light propulsion of matter is observed on a macroscopic scale using a bulk graphene-based material. The unique structure and properties of graphene, and the novel morphology of the bulk three-dimensional linked graphene material make it capable not only of absorbing light at various wavelengths but also of emitting energetic electrons efficiently enough to drive the bulk material, following Newtonian mechanics. Thus, the unique photonic and electronic properties of individual graphene sheets are manifested in the response of the bulk state. These results offer an exciting opportunity to bring about bulk-scale light manipulation with the potential to realize long-sought applications in areas such as the solar sail and space transportation driven directly by sunlight. © 2015 Nature Publishing Group

Hu Z.,University of California at Santa Barbara | Hu Z.,Nankai University | Metiu H.,University of California at Santa Barbara
Journal of Physical Chemistry C | Year: 2012

We use density functional theory to examine the dissociation of halogen molecules on CeO 2(111). We are interested in this because oxides are used to catalyze the oxihalogenation of alkanes. Our calculations show that the exothermicity of the dissociative adsorption is increased substantially if one of the dissociation fragments is a Lewis acid and the other is a Lewis base. Doping the CeO 2 surface to turn it into an acid or a base can be used to influence strongly halogen dissociation. Finally, we show that the presence of a halogen on the oxide surface facilitates the breaking of the C-H bond in methane. © 2012 American Chemical Society.

Li D.,CAS Dalian Institute of Chemical Physics | Li D.,Nankai University | Wang Y.,CAS Dalian Institute of Chemical Physics | Han K.,CAS Dalian Institute of Chemical Physics
Coordination Chemistry Reviews | Year: 2012

Cytochrome P450 (P450) enzymes are the major catalysts involved in the oxidative metabolism of most drugs, steroids, carcinogens, and other chemicals. They catalyze a variety of reactions and convert chemicals to potentially reactive products as well as make compounds less toxic. More than 75% of drugs in clinical use are metabolized by P450s. Understanding the mechanism of drug metabolism by P450, in particular the chemical process, is indispensable in the early phases of drug discovery process. In this review, we discuss our recent theoretical studies on the mechanism of some specific compounds catalyzed by P450. Density functional theory (DFT) is used as the quantum mechanical (QM) tool to explore the fundamental mechanism of these reactions. These DFT calculations provide structures, energies, and some other properties of transition states and intermediates and thus shed light on the electronic factors that govern the stability and reactivity. These theoretical studies provide a complementary insight to experiment and suggest some new features. DFT serves a powerful tool to explore the chemical mechanism of drug metabolism by P450. The revealed fundamental mechanism concerning how the enzyme catalyzes the drug metabolism, especially the transition state of the rate-determining reaction step, could provide a valuable mechanistic base for rational design of novel drugs. © 2012 Elsevier B.V.

Han J.,Nankai University
Journal of Materials Chemistry C | Year: 2013

Liquid crystals with 1,3,4-oxadiazole units in the aromatic core have attracted considerable attention due to their rich mesophases, high photoluminescence quantum yields, good electron transporting ability and excellent thermal stabilities. In this feature article, 1,3,4-oxadiazole-based liquid crystals are classified into three categories according to their different molecular shapes and molecular weight: calamitic and discotic monomers, symmetric and non-symmetric dimers, and polymers including main-chain, side-chain and mesogen-jacketed types. The structure-property relationships of this kind of liquid crystal are discussed in-depth, with an emphasis on strategies to devise columnar and biaxial nematic mesophases with a low temperature range. © 2013 The Royal Society of Chemistry.

An electrochemiluminescent (ECL) lead biosensor was developed based on GR-5 lead-dependent DNAzyme for lead recognition and intercalated ruthenium tris(1,10-phenanthroline) (Ru(phen)(3)(2+)) as the ECL probe. The thiol-modified substrate was first immobilized on the surface of the gold electrode via gold-sulfur self-assembly. Subsequently, the hybridization of DNAzyme and its substrate and the automatic intercalation of Ru(phen)(3)(2+) proceeded. Intercalated Ru(phen)(3)(2+) can transfer electrons through double-stranded DNA to the electrode and its electrochemiluminescence was excited with a potential step using tripropylamine as the coreactant. In the presence of lead, the substrate cleaves at the scissile ribo-adenine into two fragments. The dissociation of DNAzyme occurs, leading to the releasing of intercalated Ru(phen)(3)(2+) accompanied by a decrease in the intensity of electrochemiluminescence. A quantity of lead can be calculated from this decrease. The biosensor is highly sensitive and specific, along with an ultra-low limit of detection of 0.9 pM and a dynamic range from 2 to 1000 pM. It enables analysis of trace amounts of lead in serum samples. The combination of the intercalated-Ru(phen)(3)(2+) ECL probe and the cofactor-dependent DNAzyme may push the performance of cofactor-sensing tactics to the extreme.

Li C.-T.,University of Warwick | Li Y.,Nankai University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2012

The last few years have seen the use of photo response non-uniformity noise (PRNU), a unique fingerprint of imaging sensors, in various digital forensic applications such as source device identification, content integrity verification, and authentication. However, the use of a color filter array for capturing only one of the three color components per pixel introduces color interpolation noise, while the existing methods for extracting PRNU provide no effective means for addressing this issue. Because the artificial colors obtained through the color interpolation process are not directly acquired from the scene by physical hardware, we expect that the PRNU extracted from the physical components, which are free from interpolation noise, should be more reliable than that from the artificial channels, which carry interpolation noise. Based on this assumption we propose a couple-decoupled PRNU (CD-PRNU) extraction method, which first decomposes each color channel into four sub-images and then extracts the PRNU noise from each sub-image. The PRNU noise patterns of the sub-images are then assembled to get the CD-PRNU. This new method can prevent the interpolation noise from propagating into the physical components, thus improving the accuracy of device identification and image content integrity verification. © 2011 IEEE.

Zheng W.,Nankai University
Crystal Growth and Design | Year: 2010

Ultrathin BiOCl nanoflakes, nanoplate arrays, and curved nanoplates have been successfully synthesized via an ionothermal synthetic route by using an ionic liquid 1-hexadecyl-3-methylimidazolium chloride ([C16Mim]Cl) as "all-in-one" solvent, simply adjusting reaction temperature. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared spectroscopy (FT-IR), separately. Possible formation mechanisms of various nanostructures were proposed in terms of crystal growth habit and dynamics. In addition, the excellent adsorption performance of the as-prepared BiOCl nanoplates makes them useful with potential applications in the aspect of wastewater treatment. © 2010 American Chemical Society.

Tian H.,East China Normal University | Jia Q.-X.,East China Normal University | Gao E.-Q.,East China Normal University | Wang Q.-L.,Nankai University
Chemical Communications | Year: 2010

The flexibility of the 3D framework derived from Ni(ii) and an aromatic dicarboxylate allows for the incorporation of different second bridges, and the resulting materials can be a metamagnet or a paramagnet depending upon the length of the second bridge. © 2010 The Royal Society of Chemistry.

Zi G.,Beijing Normal University | Zhang F.,Beijing Normal University | Song H.,Nankai University
Chemical Communications | Year: 2010

A highly enantioselective group 5 metal amide catalyst system is reported for the hydroaminoalkylation of secondary amines to give chiral amines in good yields with excellent ee values (up to 93%) by loading of 5% precatalyst. © 2010 The Royal Society of Chemistry.

Yoo H.,Incheon National University | Kim J.,Incheon National University | Zhang L.,Nankai University
Current Applied Physics | Year: 2012

We made Cu 2ZnSnS 4 (CZTS) thin films by sulfurization of Cu/Sn/Cu/Zn metallic films. Sulfurizations were carried out under different thermal annealing conditions, where maximum temperatures were 440 °C (LT-CZTS) and 550°C (HT-CZTS). For LT-CZTS films, secondary phases such as SnS 2 and Cu 2-xS were observed, whereas for HT-CZTS films secondary impurities were not detected. Chemical composition of LT-CZTS film was observed to be very non-uniform. Highly Sn-rich and Zn-rich regions were found on the film surface of LT-CZTS. However, averaged chemical composition for larger area was close to stoichiometry. The HT-CZTS film showed homogeneous structural and chemical composition features. But, for HT-CZTS film, the Sn composition was observed to be decreased, which was due to the Sn-loss. By UV-Visible spectroscopy, optical band gaps of LT- and HT-CZTS films were measured to be ∼1.33 eV and ∼1.42 eV, respectively. The band gap of LT-CZTS film was also observed to be smaller by photoluminescence measurement. The depressed band gap of LT-CZTS film may be ascribed to some defects and low band gap impurities such as Cu 2SnS 3 and Cu 2-xS in the LT-CZTS film. © 2011 Elsevier B.V. All rights reserved.

Purpose: The purpose of this paper is to examine the multifaceted information disadvantages facing the so-called information poor in today's society. It has two specific objectives: to identify, from the empirical evidence of individuals' daily and regular information practices, meaningful constructs for defining information inequality; and to investigate how the "information poor" characterise on these constructs in comparison with others. Design/methodology/approach: The study developed its findings in relation to the above objectives inductively from the interview transcripts of 73 people of different social statuses and occupations regarding their daily and regular information practices. Findings: Three concepts emerged as meaningful constructs to define information inequality, hence to describe the information poor: individuals' information resource bases, information practices, and information assets. The information poor are found to be disadvantaged in all these aspects. They are first disadvantaged by limited freedom and/or opportunities in claiming society's vast and rapidly increasing information resources into their own information resource bases; then by the constraint of their information practices in developing their information resource bases and obtaining information utilities from these resources; and further more by impoverished information assets to empower themselves in normal and problematic situations. Practical implications: Understanding of the information poor as sketched above will likely demand further research into a number of issues/areas hitherto ignored by information inequality studies. Originality/value: This paper is one of the first to address empirically one of the most fundamental questions in information inequality studies; it extends library and information science understanding of the information poor hitherto dominated by the information deficiency thesis. © Emerald Group Publishing Limited.

Li Y.,Nankai University | Belkin N.J.,Rutgers University
Journal of the American Society for Information Science and Technology | Year: 2010

This study explores the relationships between work task and interactive information search behavior. Work task was conceptualized based on a faceted classification of task. An experiment was conducted with six work-task types and simulated work-task situations assigned to 24 participants. The results indicate that users present different behavior patterns to approach useful information for different work tasks:They select information systems to search based on the work tasks at hand, different work tasks motivate different types of search tasks, and different facets controlled in the study play different roles in shaping users' interactive information search behavior. The results provide empirical evidence to support the view that work tasks and search tasks play different roles in a user's interaction with information systems and that work task should be considered as a multifaceted variable. The findings provide a possibility to make predictions of a user's information search behavior from his or her work task, and vice versa. Thus, this study sheds light on task-based information seeking and search, and has implications in adaptive information retrieval (IR) and personalization of IR. © 2010 ASIS&T.

Chen H.,Nankai University | Shahbazpanahi S.,University of Ontario Institute of Technology
IEEE Transactions on Signal Processing | Year: 2012

In filter-and-forward (FF) based two-way relay networks, each transmission for data exchange between two transceivers consists of only two time slots (or phases). In the first time slot, both transceivers transmit their data simultaneously to the relays. The received signal of each relay is filtered using a finite impulse response (FIR) filter to compensate for the frequency selectivity of the channels, and then, the output of the filter is forwarded to both transceivers in the second time-slot. In this paper, new approaches to distributed cooperative beamforming for such two-way relay networks with frequency selective channels are proposed. The first two distributed beamforming approaches assume that the transmitted powers of the transceivers are given and fixed. The first beamformer is based on minimizing the total transmitted power of the relays subject to two constraints on the signal-to-inter-symbol- interference-plus-noise ratio (SINR) at both transceivers. The second beamformer is designed through maximization of the lowest SINR of the two transceivers while keeping the relay transmitted power under certain levels. We show that these two problems can be cast as second-order convex cone programming problems. The other two distributed beamforming methods aim to calculate the transmitted powers of the transceivers as well as the coefficients of the relay filters using two different beamforming techniques. The first technique is based on the minimization of the total transmitted power of the transceivers and the relays subject to the SINR requirements for both transceivers, and the second method maximizes the lowest SINR of the two transceivers subject to a constraint on the total transmitted power. Simulation results demonstrate that using an FF relaying strategy can significantly improve the underlying performance measure as compared to the traditional amplify-and-forward relaying approach. © 2011 IEEE.

Zhang Q.Q.,Nankai University
Physics in medicine and biology | Year: 2012

To quantify OCT images of rectal tissue for clinic diagnosis, the scattering coefficient of the tissue is extracted by curve fitting the OCT signals to a confocal single model. A total of 1000 measurements (half and half of normal and malignant tissues) were obtained from 16 recta. The normal rectal tissue has a larger scattering coefficient ranging from 1.09 to 5.41 mm-1 with a mean value of 2.29 mm-1 (std:±0.32), while the malignant group shows lower scattering property and the values ranging from 0.25 to 2.69 mm-1 with a mean value of 1.41 mm-1 (std:±0.18). The peri-cancer of recta has also been investigated to distinguish the difference between normal and malignant rectal tissue. The results demonstrate that the quantitative analysis of the rectal tissue can be used as a promising diagnostic criterion of early rectal cancer, which has great value for clinical medical applications.

Liang J.,University of California at Los Angeles | Li L.,University of California at Los Angeles | Tong K.,University of California at Los Angeles | Ren Z.,University of California at Los Angeles | And 4 more authors.
ACS Nano | Year: 2014

Transparent conductive electrodes with high surface conductivity, high transmittance in the visible wavelength range, and mechanical compliance are one of the major challenges in the fabrication of stretchable optoelectronic devices. We report the preparation of a transparent conductive electrode (TCE) based on a silver nanowire (AgNW) percolation network modified with graphene oxide (GO). The monatomic thickness, mechanical flexibility, and strong bonding with AgNWs enable the GO sheets to wrap around and solder the AgNW junctions and thus dramatically reduce the inter-nanowire contact resistance without heat treatment or high force pressing. The GO-soldered AgNW network has a figure-of-merit sheet resistance of 14 ohm/sq with 88% transmittance at 550 nm. Its storage stability is improved compared to a conventional high-temperature annealed AgNW network. The GO-soldered AgNW network on polyethylene terephthalate films was processed from solutions using a drawdown machine at room temperature. When bent to 4 mm radius, its sheet resistance was increased by only 2-3% after 12 000 bending cycles. GO solder can also improve the stretchability of the AgNW network. Composite TCE fabricated by inlaying a GO-soldered AgNW network in the surface layer of polyurethane acrylate films is stretchable, by greater than 100% linear strain without losing electrical conductivity. Fully stretchable white polymer light-emitting diodes (PLEDs) were fabricated for the first time, employing the stretchable TCE as both the anode and cathode. The PLED can survive after 100 stretching cycles between 0 and 40% strain and can be stretched up to 130% linear strain at room temperature. © 2014 American Chemical Society.

We propose a coherent-form energy conservation relation (ECR) that is generally valid for the elastic transmission and reflection of a guided mode in a symmetric scattering system. In contrast with the classical incoherent-form ECR, t2 + ρ2δ1 with t and ρ denoting the elastic transmission and reflection coefficients of a guided mode, the coherentform ECR is expressed as t + ρ=1, which imposes a constraint on a coherent superposition of the transmitted and reflected modes. The coherent-form ECR is rigorously demonstrated and is numerically tested by considering different types of modes in various scattering systems. Further discussions with the scattering matrix formalism indicate that two coherentform ECRs, t + ρ δ1 and tρ δ1, along with the classical ECR t2 + ρ2δ1 constitute a complete description of the energy conservation for the elastic scattering of a guided mode in a symmetric scattering system. The coherent-form ECR provides a common tool in terms of energy transfer for understanding and analyzing the scattering dynamics in currently interested scattering systems. © 2013 Optical Society of America.

Gu Z.,Nankai University | Zhang S.,Chongqing University of Posts and Telecommunications
International Journal of Production Economics | Year: 2012

Based on incomplete contract theories, we studied the strategic behaviors of up-stream and down-stream manufacturers by option game model and obtain some conclusions. First, the down-streams pay-off function is a concave function of its investment in fixed assets, so there is an optimal investment, which ensures the down-streams maximal pay-off and prevents it from being holdup. Second, in presence of endogenous default risks, the up-stream can improve its pay-off level through non-linear pricing. Last, increasing business risks of the down-stream may lead to an increased price fluctuation of the up-stream, while the down-streams technological advancement can make such fluctuation less. © 2010 Elsevier B.V. All rights reserved.

Huang P.-Q.,Xiamen University | Huang P.-Q.,Nankai University | Ou W.,Xiamen University | Xiao K.-J.,Xiamen University | Wang A.-E.,Xiamen University
Chemical Communications | Year: 2014

We report one-pot and chemoselective Knoevenagel-type reactions using highly stable amides and lactams as the electrophilic substrates. The method is based on the in situ activation of amide carbonyl with triflic anhydride and a subsequent reaction with carbanions generated in situ from carbonyl compounds. The amide-based method is an alternative to the versatile thioamide-based Eschenmoser sulfide contraction. © 2014 the Partner Organisations.

Chen P.,Tianjin University | Zhong Y.,Tianjin University | Liu H.,Nankai University
Optics Letters | Year: 2013

Light absorption by thin-film amorphous Si solar cells patterned with metallic nanogratings is investigated theoretically. Propagative bounded modes that include the surface plasmon polariton (SPP) and the photonic mode (PM) are extracted from the total field to quantitatively evaluate their contribution to the light absorption. Our results show that after removing the propagative bounded modes from the total field, the residual field still contributes to a major part of the total light absorption. This proves, at a quantitative level, that the light absorption of the structure is largely attributed to the residual field that is composed of unbounded or evanescent modes arising from the grating scattering, and the SPP and the PM do not play a dominant role, which is out of the previous intuitive expectations. © 2013 Optical Society of America.

Liu P.,University of California at Los Angeles | Xu X.,University of California at Los Angeles | Xu X.,Nankai University | Dong X.,University of California at Los Angeles | And 4 more authors.
Journal of the American Chemical Society | Year: 2012

The mechanism and origins of Z-selectivity in olefin metathesis with chelated Ru catalysts were explored using density functional theory. The olefin approaches from the "side" position of the chelated Ru catalysts, in contrast to reactions with previous unchelated Ru catalysts that favor the bottom-bound pathway. Steric repulsions between the substituents on the olefin and the N-substituent on the N-heterocyclic carbene ligand lead to highly selective formation of the Z product. © 2012 American Chemical Society.

Cao Y.,Hong Kong Polytechnic University | Jin W.,Hong Kong Polytechnic University | Ho L.H.,Hong Kong Polytechnic University | Liu Z.,Hong Kong Polytechnic University | Liu Z.,Nankai University
Optics Letters | Year: 2012

We demonstrate gas detection based on evanescent-wave photoacoustic (PA) spectroscopy with tapered optical fibers. Evanescent-field instead of open-path absorption is exploited for PA generation, and a quartz tuning fork is used for PA detection. A tapered optical fiber with a diameter down to the wavelength scale demonstrates detection sensitivity similar to an open-path system but with the advantages of easier optical alignment, smaller insertion loss, and multiplexing capability. © 2012 Optical Society of America.

In the present study, a superhydrophobic polyurethane (PU) sponge with hierarchically structured surface, which exhibits excellent performance in absorbing oils/organic solvents, was fabricated for the first time through mussel-inspired one-step copolymerization approach. Specifically, dopamine (a small molecular bioadhesive) and n-dodecylthiol were copolymerized in an alkaline aqueous solution to generate polydopamine (PDA) nanoaggregates with n-dodecylthiol motifs on the surface of the PU sponge skeletons. Then, the superhydrophobic sponge that comprised a hierarchical structured surface similar to the chemical/topological structures of lotus leaf was fabricated. The topological structures, surface wettability, and mechanical property of the sponge were characterized by scanning electron microscopy, contact angle experiments, and compression test. Just as a result of the highly porous structure, superhydrophobic property and strong mechanical stability, this sponge exhibited desirable absorption capability of oils/organic solvents (weight gains ranging from 2494% to 8670%), suggesting a promising sorbents for the removal of oily pollutants from water. Furthermore, thanks to the nonutilization of the complicated processes or sophisticated equipment, the fabrication of the superhydrophobic sponge seemed to be quite easy to scale up. All these merits make the sponge a competitive candidate when compared to the conventional absorbents, for example, nonwoven polypropylene fabric. © 2014 American Chemical Society.

Yuan G.,Nanyang Technological University | Wang Q.,Nanyang Technological University | Yuan X.,Nankai University
Optics Letters | Year: 2012

Dynamic generation of plasmonic Moiré fringes using a phase engineered optical vortex (OV) beam is experimentally demonstrated. Owing to the unique helical phase carried by an OV beam, the initial phase of surface plasmon polaritons (SPPs) emanating from a metallic grating can be adjusted dynamically by changing the phase hologram displayed on a spatial light modulator. Plasmonic Moiré fringes are readily achieved by overlapping two SPP standing waves with certain angular misalignment, excited by the positive and negative topological charge components, respectively, of a cogwheel-like OV beam. The near-field scanning optical microscopy measurement result of SPP distributions has shown a good agreement with the numerical predictions. © 2012 Optical Society of America.

Li B.,Korea Basic Science Institute | Li B.,Korea Advanced Institute of Science and Technology | Li B.,Nankai University | Park Y.,Korea Basic Science Institute | And 3 more authors.
Journal of the American Chemical Society | Year: 2014

We report herein a new strategy of the Ru-catalyzed intramolecular olefin hydrocarbamoylation for the regiodivergent synthesis of five- and six-membered benzo-fused lactams starting from N-(2-alkenylphenyl)formamides. Using a combined catalyst of Ru3(CO)12/Bu4NI in DMSO/toluene cosolvent (catalytic system A), a 5-exo-type cyclization proceeds favorably to form indolin-2-ones as a major product in good to excellent yield. When the reaction was conducted in the absence of halide additives in DMA/PhCl (catalytic system B), 3,4-dihydroquinolin-2-ones were obtained in major in moderate to high yield via a 6-endo cyclization process. An excellent level of regioselectivity was observed with a variety of substrates to deliver 5-exo- or 6-endo-cyclized lactams. It was found that while the selective cyclization was controlled primarily by the choice of catalytic systems employed, it was also greatly influenced by the structural nature of substrates. A halide-bridged trinuclear complex [Ru3(CO)10(μ2-I)] - is postulated to be an active species in the catalytic system A. Two reaction pathways are proposed, in which the Ru-catalyzed oxidative addition of formyl C-H or N-H bond initiates the subsequent cyclization processes. © 2013 American Chemical Society.

Teng H.-L.,Wuhan University | Yao L.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Journal of the American Chemical Society | Year: 2014

An unprecedented Cu(I)-catalyzed asymmetric [6 + 3] cycloaddition of tropone with azomethine ylides was reported, which performs well over a broad scope of substrates and offers a unique and facile access to the synthetically useful bridged azabicyclo[4.3.1]decadiene derivatives in good yields with high levels of diastereoselectivities and enantioselectivities under mild conditions. © 2014 American Chemical Society.

Li X.-Q.,Nankai University | Liu X.,Lanzhou University
European Physical Journal C | Year: 2014

Based on the fact that the long expected pentaquark which possesses the exotic quantum numbers of B=1 and S=1 was not experimentally found, although exotic states of XYZ have been observed recently, we conjecture that the heavy flavors may play an important role in stabilizing the hadronic structures beyond the traditional qq¯ and qqq composites. © 2014, The Author(s).

Wang H.,Nanjing University of Posts and Telecommunications | Deng S.,Nankai University
Nonlinear Analysis: Real World Applications | Year: 2013

A Finsler manifold (M,F) is called Einstein if its Ricci scalar does not depend on the flagpole. We obtain new examples of homogenous Einstein-Randers metrics on some Stiefel manifolds SO(n)SO(l), as well as the symplectic analogs Sp(n)Sp(l). An existence result of invariant Einstein-Randers metrics is also obtained on these homogeneous manifolds. We also give a classification of these metrics under isometries and determine their group of isometries. © 2012 Published by Elsevier Ltd.

Cui H.,Nanjing Agricultural University | Cui C.,Nankai University
Dalton Transactions | Year: 2015

Reaction of the N-heterocyclic carbene (NHC)-stabilized silylene ArN(SiMe3)Si(IiPr)Cl (1, Ar = 2,6-iPr2C6H3, IiPr = 1,3-diisopropyl-4,5-dimethyl-imidazol-2-ylidene) with SiCl4 resulted in the formation of three different products NHC-stabilized dichlorosilaimine ArNSi(IiPr)Cl2 (2), aminotrichlorosilane ArN(SiMe3)SiCl3 (3) and a silaimine dimer (ArNSiCl2)2 (4) under different conditions. The products can be controlled by reaction conditions. Compound 2 is the first example of a less bulky NHC-supported silaimine via the reaction of a silylene with SiCl4. © 2015 The Royal Society of Chemistry.

As a new class of synthetic receptors, molecularly imprinted polymers (MIPs) have shown great potential in many applications because of their good specific recognition ability, high stability, and easy preparation. The ultimate goal of molecular imprinting is to obtain MIPs that can be routinely used as alternatives to natural antibodies and receptors. However, the presently developed MIPs targeting small organic molecules mostly fail to show specific bindings in aqueous solutions, which is in sharp contrast to biological receptors and significantly limits their practical applications in such areas as biomimetic assays and sensors. Many efforts have been devoted to address this issue in the past two decades. In this feature article, I provide a detailed overview of the progress made in the development of water-compatible MIPs with an emphasis on our strategies to solve this challenging problem. Moreover, some still existing challenges and future prospects in this research area are also presented. © 2014 Elsevier Ltd. All rights reserved.

Peng S.,Central China Normal University | Wang Z.-Q.,Nankai University | Wang Z.-Q.,Utah State University
Archive for Rational Mechanics and Analysis | Year: 2013

We consider the following nonlinear Schrödinger system in ℝ3, where P(r) and Q(r) are positive radial potentials, μ > 0, ν > 0 and β ∈ ℝ is a coupling constant. This type of system arises, in particular, in models in Bose-Einstein condensates theory. We examine the effect of nonlinear coupling on the solution structure. In the repulsive case, we construct an unbounded sequence of non-radial positive vector solutions of segregated type, and in the attractive case we construct an unbounded sequence of non-radial positive vector solutions of synchronized type. Depending upon the system being repulsive or attractive, our results exhibit distinct characteristic features of vector solutions. © 2012 Springer-Verlag Berlin Heidelberg.

Li J.,Hong Kong University of Science and Technology | Tsung F.,Hong Kong University of Science and Technology | Zou C.,Nankai University
Journal of Quality Technology | Year: 2012

We consider statistical process control of multivariate categorical processes and propose a Phase II log-linear directional control chart that exploits directional shift information and integrates the monitoring of multivariate categorical processes into the unified framework of multivariate binomial and multivariate multinomial distributions. We also suggest a diagnostic scheme for identifying the shift direction. Both the control chart and the diagnostic approach are simple and easily computed. Numerical simulations and real applications are presented to demonstrate their effectiveness.

In this account we have systematically described the acid-promoted intramolecular cycloadditions of activated cyclo-propanes, which were conceptually classified into intramolecular cross-cycloadditions (IMCC) and intramolecular parallel-cyclo-additions. The IMCC provided a general and efficient strategy for construction of structurally complex and diverse bridged bicyclic skeletons. The potential of this strategy has been demonstrated by the synthesis of natural products. 1 Introduction 2 [3+2]IMCC of Cyclopropane 1,1-Diester with C=O 3 [3+2]IMCC of Cyclopropane 1,1-Diester with C=N 4 [3+2]IMCC of Cyclopropane 1,1-Diester with C=C 5 [3+3]IMCC of Cyclopropane 1,1-Diester with Nitrones 6 [3+2]IMCC of Mono-donor/Mono-acceptor Cyclopropane with C=O 7 Lewis Acid Regulated Domino Cycloisomerization/[4+2]IMCC or [3+2]IMCC of Alkynylcyclopropane Ketone with C=O and C=N 8 Conclusions and Outlook. © Georg Thieme Verlag.

Xin W.,Chinese PLA General Hospital | Wei W.,Nankai University | Li X.-Y.,Chinese PLA General Hospital
American Journal of Clinical Nutrition | Year: 2013

Background: The effects of fish oil on heart rate variability in humans remain unclear. Objective: A meta-analysis of randomized controlled trials was performed to investigate the influence of fish oil on heart rate variability. Design: Human intervention studies were identified by systematic search of PubMed, Embase, The Cochrane Library, and references of related reviews and studies. A random-effects model was applied to estimate the pooled results. Results: Fifteen studies were included. Results of the meta-analysis showed that the SD of normal-to-normal interval [standardized mean difference (SMD) = 0.10, P = 0.35] and square of successive differences (SMD = 0.05, P = 0.35), 2 of the time-domain parameters of heart rate variability, were not significantly influenced by fish-oil supplementation. For the frequency-domain parameters, the high-frequency power (HF), a surrogate of vagal function, was significantly increased by fish-oil supplementation (SMD = 0.30, P = 0.005), the low-frequency power (LF) was not significantly affected (SMD = 0.03, P = 0.79), and the ratio of LF to HF (LF/HF) showed a trend of reduction (SMD = 20.22, P = 0.08). The trend for a treatment effect on LF/HF became significant at P = 0.01 when the 2 studies with a dose <1000 mg/d were omitted. Subgroup analyses according to predefined study characteristics showed no significant results. Conclusion: Short-term fish-oil supplementation may favorably influence the frequency domain of heart rate variability, as indicated by an enhanced vagal tone, which may be an important mechanism underlying the antiarrhythmic and other clinical effects of fish oil. © 2013 American Society for Nutrition.

An L.,Nankai University | Tong L.,Hebei University of Technology
Knowledge-Based Systems | Year: 2010

Rough sets theory has proved to be a useful mathematical tool for dealing with the vagueness and granularity in information tables. Classical definitions of lower and upper approximations were originally introduced with reference to an indiscernibility relation. However, indiscernibility relation is still restrictive for many applications. Many real-world problems deal with assignment of some objects to some preference-ordered decision classes. And, the objects are described by a finite set of qualitative attributes and quantitative attributes. In this paper, we construct the indiscernibility relation for the subset of nominal attributes, the outranking relation for the subset of ordinal attributes, and the similarity relation for the subset of quantitative attributes. Then the global binary relation is generated by the intersection of indiscernibility relation, outranking relation and similarity relation. New definitions of lower and upper approximations of the upward and downward unions of decision classes are proposed based on the global relation. We also prove that the lower and upper approximation operations satisfy the properties of rough inclusion, complementarity, identity of boundaries, and monotonicity. © 2010 Elsevier B.V. All rights reserved.

A novel cascade carbo-carbonylation reaction of unactivated arylalkenes with ketones or aldehydes was catalyzed by an organocatalyst and a transition metal catalyst via a SOMO-enamine under air, affording a simple approach to γ-diketones and γ-carbonyl aldehydes. © The Royal Society of Chemistry 2010.

Nair U.,University of Michigan | Cao Y.,University of Michigan | Xie Z.,University of Michigan | Xie Z.,Nankai University | Klionsky D.J.,University of Michigan
Journal of Biological Chemistry | Year: 2010

Atg18 and Atg21 are homologous WD-40 repeat proteins that bind phosphoinositides via a novel conserved Phe-Arg-Arg-Gly motif and function in autophagy-related pathways. Atg18 is required for the cytoplasm to vacuole targeting (Cvt) pathway and autophagy, whereas Atg21 is only required for the Cvt pathway. Currently, the functions of both proteins are poorly understood. Here, we examined the relationship between the phosphatidylinositol 3-phosphate (PtdIns(3)P)-binding abilities of Atg18 and Atg21 and autophagy by expressing variants of these proteins that have mutations in their phosphoinositide-binding motifs. Cells expressing PtdIns(3)P-binding mutants of both these proteins showed highly reduced autophagy. Furthermore, the localization of components of two related ubiquitin-like protein conjugation systems, Atg8 and Atg16, to the phagophore assembly site is affected. Consistent with the aberrant localization of the above Atg proteins, precursor Ape1, a cargo of the Cvt pathway and autophagy, is partially protease-sensitive in starvation conditions. This finding suggests a requirement for the PtdIns(3)P binding capability of Atg18 and Atg21 in efficient completion of the sequestering autophagic vesicles. Finally, using a multiple knock-out strain, we found that Atg18 and Atg21 facilitate the recruitment of Atg8-PE to the site of autophagosome formation and protect it from premature cleavage by Atg4, which represents a key aspect of post-translational autophagy regulation. Taken together, our results suggest that PtdIns(3)P binding by at least Atg18 or Atg21 is required for robust autophagic activity and that the PtdIns(3)P-binding motifs of Atg18 and Atg21 can compensate for one another in the recruitment of Atg components that are dependent on PtdIns(3)P for their phagophore assembly site association. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

Bian L.,Nankai University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The naturalness problem may be studied on the complex two-dimensional plane with the technique of dimensional regularization. The renormalization group equation of the Higgs mass on the plane suggests the Higgs mass approaches zero at the ultraviolet scale; the scale can be Planck scale when the top quark pole mass Mt=168 GeV. The real issue of the naturalness problem in the sense of the Wilsonian renormalization group method is not about quadratic divergences but the rescaling effect. The Higgs mass can be considered to be one composed mass. All terms in the Lagrangian in this scenario are marginal terms and no relevant terms are left; thus, no rescaling effect exists to cause the naturalness problem. The renormalization group equation of the vacuum expectation value in the Landau gauge up to two-loop order is studied. Scale-dependent behavior of the composed Higgs mass shows that we can have one tiny Higgs mass at the high energy scale, even around the Planck scale, when Mt≤170.7 GeV. © 2013 American Physical Society.

Han D.,University of Central Florida | Sun W.,Nankai University
IEEE Transactions on Information Theory | Year: 2014

We propose new approaches to the problems of recovering signals from the rearranged frame coefficients or frame coefficients with erasures at either known or unknown locations. These problems naturally arise from applications, where the encoded information needs to be transmitted, for example, in signal/image processing, information and coding theory, and communications. We show that with the appropriate choices of the frames that are used for encoding, the signal with erasures occurring at known locations can be easily recovered without inverting the (sub)frame operators each time. Our new easy to implement and cost-efficient algorithm provides perfect reconstruction of the original signal. To address the problem of recovering erased coefficients from unknown locations, we propose to use a class of frames that are almost robust with respect to \(m\) -erasures. We prove that every frame with uniform excess can be rescaled to an almost robust frame and the locations of erased data can be perfectly recovered for almost all the signals. Similar results are obtained for recovering the original order of a disordered (rearranged) set of frame coefficients. Numerical examples are presented to test the main results. Whenever the received data are noise free, we can recover the original signal exactly from frame coefficients with erasures at unknown locations or from a disordered set of frame coefficients. © 2014 IEEE.

Fang X.,Wuhan University | Li Q.-H.,Wuhan University | Tao H.-Y.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Advanced Synthesis and Catalysis | Year: 2013

The first organocatalytic asymmetric addition of thiols to trifluoromethylaldimine for the construction of chiral trifluoromethylated N,S-acetals has been achieved in high yields (up to 99%) and excellent enantioselectivities (up to 95% ee) with 1 mol% of a bifunctional organocatalyst. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu X.,Zhejiang University | Chen W.,Zhejiang University | Chen W.,Nankai University
Organometallics | Year: 2012

[Ru 2Cl(L)(CH 3CN) 4](PF 6) 3 (1, L = 3,6-bis(N-(pyridylmethyl)imidazolylidenyl)pyridazine), [Cu 3L a 3](PF 6) 3 (2, L a = 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine), [Pd 2(allyl) 2L](PF 6) 2 (3), [Pd 2(allyl) 2L b 2](PF 6) 2 (4, L b = N-pyridylmethylimidazole), and [NiL c 2](PF 6) 2 (5, L c = 3-(N-(pyridylmethyl) imidazolylidenyl)-6-methoxylpyridazine) have been synthesized and fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. In complex 1, ligand L binds to two Ru(II) centers, forming a well-behaved Ru 2(L)Cl plane with a five-membered metallocyclic ring. Complex 2 is trinuclear, containing a triangular Cu 3 unit bonded together by three 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine, where one imidazolylidene was oxidized into imidazolone. Deprotonation reaction with Ag 2O in CH 3CN and CH 3OH resulted in C-N cleavage of the imidazolium salt, and subsequent reaction with [Pd(allyl)Cl] 2 and Ni(PPh 3) 2Cl 2 gave 4 and 5, respectively. Dinuclear Ru(II)-NHC complex 1 exhibits excellent catalytic activity for the oxidation of alkenes into diketones. © 2012 American Chemical Society.

Histidine functionalized multi-walled carbon nanotubes (MWCNTs-His) were synthesized for selective preconcentration of V(V). Using flow injection coupled with electrothermal atomic absorption spectrometric strategy, an on-line ultrasensitive determination of V(V) in biological and environmental samples was achieved. Statical and dynamical adsorption of V(V) with MWCNTs-His was carefully evaluated. Isotherm and kinetics of adsorption were studied and fitted in the Langmuir model. The MWCNTs-His sorbent was demonstrated to be good column packings for on-line preconcentration. All of the experimental conditions with MWCNT-His packed microcolumn for the preconcentration and determination of V(V) were investigated in detail. Including the optimal sample's pH, sample's flow rate, loading time, eluting solution and interfering ions were performed on-line, to ensure automatic determination with a high precision. With a consumption of 5.0mL sample solution and a preconcentration time of 1min, an enhancement factor of 35 with a detection limit (3s) of 9ngL -1 or 0.2nM is achieved. The sample throughput and the precision (RSD) for 11 replicate measurements of 400ngL -1 level was 28h -1 and 1.5%, respectively. The method was applied to the determination of trace V(V) in a variety of biological and environmental samples. © 2012 Elsevier B.V.

Keller E.T.,University of Michigan | Li L.-Y.,Nankai University
Cancer Research | Year: 2011

Although it is well recognized that the tumor microenvironment plays a key role in regulating tumor progression, the mechanisms through which this occurs need to be defined. Current international research activities toward defining the role of the tumor microenvironment in cancer progression were the subject of the first Tianjin Forum on Tumor Microenvironment held at Nankai University in Tianjin, China, July 2 to 4, 2010. The importance of variety of processes, such as inflammation and angiogenesis, in the role of tumor progression was described for multiple tumor types including breast, prostate, and hepatic cancers, as well as the process of bone metastasis. Identification of novel signaling pathways that impact both angiogenesis and bone remodeling were presented. Several themes emerged from this meeting, such as: (i) tumor cells modify the microenvironment to enhance their own survival and progression; (ii) targeting host factors, in addition to targeting tumor cells, will have important therapeutic effects; and (iii) host cells distribution within the tumor has both prognostic and therapeutic significance. Several priorities for future research were defined including use of a systems biology approach to define the role of host factors in tumor progression, to define the importance of targeting both arms of the bone remodeling process for therapy of bone metastasis, and to determine how different cell subsets contribute to microenvironment-mediated regulation of tumor progression. © 2011 American Association for Cancer Research.

Liu H.,Nankai University
Advanced Nonlinear Studies | Year: 2011

In this paper, we study relationship between the stability and the growth of the number of closed characteristics on compact convex hypersurfaces in R2n, and also the stability of closed characteristics on compact convex hypersurfaces in R2n under some pinching conditions.

Xia W.,Nanjing University | Hu X.-Y.,Nanjing University | Chen Y.,Nankai University | Lin C.,Nanjing University | Wang L.,Nanjing University
Chemical Communications | Year: 2013

A novel and highly stable inclusion complex was formed between per-butylated pillar[6]arene and a ferrocenium cation, while the reduced form ferrocene only showed extremely weak binding affinity with per-butylated pillar[6]arene in organic solvents. This journal is © The Royal Society of Chemistry 2013.

Yan X.,Tsinghua University | Chen C.,Tsinghua University | Zhou Y.,Tsinghua University | Xi C.,Tsinghua University | Xi C.,Nankai University
Organic Letters | Year: 2012

Copper-catalyzed electrophilic amination of alkenylzirconocenes is accomplished under mild reaction conditions. The reaction tolerates a wide range of functional groups and can be used to prepare some hindered enamines. © 2012 American Chemical Society.

Liu H.,Nankai University | Lalanne P.,University of Bordeaux 1
Optics Express | Year: 2013

Under light illumination, metallic gratings present unexpected and fascinating phenomena, which are due to the complex charge patterns generated on the grating surfaces. The moving electrons are due to the launching of surface plasmon polaritons (SPPs), but only in part. We derive analytical expressions quantifying the plasmonic character of the surface charge patterns, i.e. the contribution of SPPs to its formation. The expressions have a general significance, in the sense that they may be applied to a variety of geometries and spectral ranges, irrespective of whether the grating absorbs, transmits, reflects, or how strongly it resonates. © 2013 Optical Society of America.

Cai S.,Tsinghua University | Chen C.,Tsinghua University | Sun Z.,Tsinghua University | Xi C.,Tsinghua University | Xi C.,Nankai University
Chemical Communications | Year: 2013

The CuCl catalyzed direct trifluoromethylation of sp2 C-H bonds has been realized, using the Togni reagent as the CF3 source. This reaction achieves the goal of regio-selectively converting C-H into C-CF 3 with ecological and readily available starting materials. © 2013 The Royal Society of Chemistry.

Li Q.-H.,Wuhan University | Wei L.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Journal of the American Chemical Society | Year: 2014

Conjugated cyclic trienes without nonbenzenoid aromatic characteristic were successfully employed as fine-tunable dipolarophiles in the Cu(I)-catalyzed asymmetric azomethine ylide-involved 1,3-dipolar [3 + 6] cycloaddition for the first time, affording a variety of bridged heterocycles bearing piperidine moiety in good yield with exclusive regioselectivity and excellent stereoselectivity. 2-Acyl group is the key factor that determines the annulation preferentially through [3 + 6]-pathway, while 2-ester group modulates the annulation through [3 + 2]-pathway. © 2014 American Chemical Society.

RNA polymerase II (PolII) is essential in gene transcription and ChIP-seq experiments have been used to study PolII binding patterns over the entire genome. However, since PolII enriched regions in the genome can be very long, existing peak finding algorithms for ChIP-seq data are not adequate for identifying such long regions. Here we propose an enriched region detection method for ChIP-seq data to identify long enriched regions by combining a signal denoising algorithm with a false discovery rate (FDR) approach. The binned ChIP-seq data for PolII are first processed using a non-local means (NL-means) algorithm for purposes of denoising. Then, a FDR approach is developed to determine the threshold for marking enriched regions in the binned histogram. We first test our method using a public PolII ChIP-seq dataset and compare our results with published results obtained using the published algorithm HPeak. Our results show a high consistency with the published results (80-100%). Then, we apply our proposed method on PolII ChIP-seq data generated in our own study on the effects of hormone on the breast cancer cell line MCF7. The results demonstrate that our method can effectively identify long enriched regions in ChIP-seq datasets. Specifically, pertaining to MCF7 control samples we identified 5,911 segments with length of at least 4 Kbp (maximum 233,000 bp); and in MCF7 treated with E2 samples, we identified 6,200 such segments (maximum 325,000 bp). We demonstrated the effectiveness of this method in studying binding patterns of PolII in cancer cells which enables further deep analysis in transcription regulation and epigenetics. Our method complements existing peak detection algorithms for ChIP-seq experiments.

Xu H.,Nanjing Southeast University | Zheng J.,Nankai University
Macromolecular Chemistry and Physics | Year: 2010

A general approach to construct one-dimensional face-to-face alignment of porphyrin/fullerene nanowires has been developed. This system uses extended trans-dihydroxotin(IV) porphyrin and trans-dicarboxylate-substituted [60]fullerenoacetic diacid compounds. The nanowires are arranged in regular one-dimensional linear arrays with lengths in the range 50-300 nm. In the nanowires, each fullerene unit is axially coordinated to the central metal ion of a Sn(IV) porphyrin unit via Sn-carboxylate coordination and forms a face-to-face aligned structure. The synthesis and the hierarchical structure of nanowires have been investigated. They could have potential applications for photoelectronic devices, organic solar cells and so on. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reduction or loss of tumor-suppressor mammalian STE20-like kinase 1 (MST1) in Hippo pathway contributes to the tumorigenesis. However, the mechanism leading to reduction of MST1 in cancers remains poorly understood. In this study, we explored the hypothesis that the oncoprotein hepatitis B X-interacting protein (HBXIP) is involved in the reduction of MST1 in breast cancer. Immunohistochemical analysis of tissue microarrays revealed that the expression of HBXIP was negatively associated with that of MST1 in 98 clinical breast tissue samples. Then we found that HBXIP could posttranslationally downregulate MST1 in breast cancer cells. Mechanistically, we identified that MST1 could be acetylated on its lysine 35 residue in the cells. Strikingly, the treatment with trichostatin A, an inhibitor of histone deacetylases (HDACs), markedly increased the levels of MST1 acetylation and protein in the cells. Interestingly, the oncoprotein HBXIP could significantly inhibit acetylation of MST1, resulting in the reduction of MST1 protein. Notably, we revealed that the HDAC6 could reduce the protein levels of MST1 through deacetylation modification of MST1 in the cells. Moreover, our data revealed that HBXIP upregulated HDAC6 at the levels of mRNA and protein by activating transcription factor nuclear factor-κB. Deacetylation of MST1 promoted the interaction of MST1 with HSC70 in the cells, resulting in a lysosome-dependent degradation of MST1 via chaperone-mediated autophagy (CMA). Functionally, the reduction of tumor-suppressor MST1 mediated by HBXIP promoted the growth of breast cancer cells in vitro and in vivo. Thus we conclude that the deacetylation of MST1 mediated by HBXIP-enhanced HDAC6 results in MST1 degradation in a CMA manner in promotion of breast cancer growth. Our finding provides new insights into the mechanism of tumor-suppressor MST1 reduction in breast cancer.Oncogene advance online publication, 14 December 2015; doi:10.1038/onc.2015.476. © 2015 Macmillan Publishers Limited

Zhang J.X.,Langfang Teachers College | Ou L.L.,Nankai University
Water Science and Technology | Year: 2013

The adsorption of crystal violet dye from aqueous solutions onto an activated carbon prepared from peanut shells was analyzed in this study. The effects of particle size, initial concentration, time and temperature on crystal violet removal were studied in batch experiments. Experimental results showed that the adsorption equilibrium was achieved within 100 min for all studied concentrations. Analysis of adsorption results showed that the adsorption isotherms could be well fitted to the Langmuir model. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients for pseudo first-order and second-order kinetic models were calculated and discussed. The results revealed that the adsorption kinetics was in good agreement with the pseudo second-order equation. Thermodynamic parameters such as the change of Gibbs free energy (ΔGW), change of enthalpy (ΔHW) and change of entropy (ΔSW) have also been determined and it has been found that the adsorption process should be spontaneous, endothermic and physisorption in nature. © IWA Publishing 2013.

Recent studies demonstrated that cancer stem cells (CSCs) have higher tumorigenesis properties than those of differentiated cancer cells and that transcriptional factor-SOX2 plays a vital role in maintaining the unique properties of CSCs; however, the function and underlying mechanism of SOX2 in carcinogenesis of lung cancer are still elusive. This study applied immunohistochemistry to analyze the expression of SOX2 in human lung tissues of normal individuals as well as patients with adenocarcinoma, squamous cell carcinoma, and large cell and small cell carcinoma and demonstrated specific overexpression of SOX2 in all types of lung cancer tissues. This finding supports the notion that SOX2 contributes to the tumorigenesis of lung cancer cells and can be used as a diagnostic probe. In addition, obviously higher expression of oncogenes c-MYC, WNT1, WNT2, and NOTCH1 was detected in side population (SP) cells than in non-side population (NSP) cells of human lung adenocarcinoma cell line-A549, revealing a possible mechanism for the tenacious tumorigenic potential of CSCs. To further elucidate the function of SOX2 in tumorigenesis of cancer cells, A549 cells were established with expression of luciferase and doxycycline-inducible shRNA targeting SOX2. We found silencing of SOX2 gene reduces the tumorigenic property of A549 cells with attenuated expression of c-MYC, WNT1, WNT2, and NOTCH1 in xenografted NOD/SCID mice. By using the RNA-Seq method, an additional 246 target cancer genes of SOX2 were revealed. These results present evidence that SOX2 may regulate the expression of oncogenes in CSCs to promote the development of human lung cancer.

Xin W.,Chinese PLA General Hospital | Wei W.,Nankai University | Li X.,Chinese PLA General Hospital
PLoS ONE | Year: 2012

Background: Effect of fish oil supplementation on flow-mediated dilation, an index of endothelial function in humans, remains controversial. We performed a meta-analysis to determine whether fish oil supplementation could improve endothelial function. Methods: Human intervention studies were identified by systematic searches of Medline, Embase, Cochrane's library and references of related reviews and studies. A random-effect model was applied to estimate the pooled results. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of fish oil supplementation on flow-mediated dilation. Results: A total of sixteen records with 1,385 subjects were reviewed. The results of the pooled analysis showed that fish oil supplementation significantly improved flow-mediated dilation (weighed mean difference: 1.49%, 95% confidence interval 0.48% to 2.50%, p = 0.004). Meta-regression and subgroup analysis suggested that the quality of included studies were inversely related to the overall effect (regression coefficient = -1.60, p = 0.04), and the significance of the effect was mainly driven by the studies with relatively poor quality. Sensitivity analysis including only double-blind, placebo-controlled studies indicated fish oil supplementation has no significant effect on endothelial function (weighed mean difference: 0.54%, 95% confidence interval -0.25% to 1.33%, p = 0.18). Besides, normoglycemic subjects or participants with lower diastolic blood pressure seemed to be associated with remarkable improvement of endothelial function after fish oil supplementation. Conclusions: Although current evidence suggested a possible role of fish oil in improving endothelial function, large-scale and high-quality clinical trials are needed to evaluate these effects before we can come to a definite conclusion. © 2012 Xin et al.

Zhang X.-X.,Nankai University | Zhang X.-X.,Humboldt University of Berlin | Liang M.,Pennsylvania State University | Ernsting N.P.,Humboldt University of Berlin | Maroncelli M.,Pennsylvania State University
Journal of Physical Chemistry B | Year: 2013

The dynamic Stokes shift of coumarin 153, measured with a combination of broad-band fluorescence upconversion (80 fs resolution) and time-correlated single photon counting (to 20 ns), is used to determine the complete solvation response of 21 imidazolium, pyrrolidinium, and assorted other ionic liquids. The response functions so obtained show a clearly bimodal character consisting of a subpicosecond component, which accounts for 10-40% of the response, and a much slower component relaxing over a broad range of times. The times associated with the fast component correlate with ion mass, confirming its origins in inertial solvent motions. Consistent with many previous studies, the slower component is correlated to solvent viscosity, indicating that its origins lie in diffusive, structural reorganization of the solvent. Comparisons of observed response functions to the predictions of a simple dielectric continuum model show that, as in dipolar solvents, solvation and dielectric relaxation involve closely related molecular dynamics. However, in contrast to dipolar solvents, dielectric continuum predictions systematically underestimate solvation times by factors of at least 2-4. © 2012 American Chemical Society.

Ren S.,Chinese University of Hong Kong | Xie Z.,Nankai University
Organometallics | Year: 2011

Reactions ofCp2Zr(μ-Cl)(μ-C 2B 10H 10)Li(OEt 2)2 (1) with various N-heterocycles derived from pyridine were studied. Treatment of 1 with pyridine, 2-bromopyridine, 2, 4-lutidine, quinoline, and 2-(1-hexynyl)pyridine generated α-C-H activation (σ-bond metathesis) products Cp2Zr(η2-C, N-C5H4N)(σ-C2B10H11) (2), Cp2Zr[η2-C,N-(6-Br-C 5H 3NN)](σ- C2B10H11) (3), Cp2Zr[η2-C,N-(4,6-Me2-C5H2N)] (σ-C2B10H11) (4), Cp2Zr(η2-C,N-C9H6N)(σ-C2B10H11) (5), and Cp2Zr- {η2-C,N-[6-(nBuCtC)-C 5H 3NN]}(σ-C2B10H11) (7), respectively. On the other hand, reaction of 1 with acridine gave the addition product 1,2-[Cp2Zr(10,9-C13H9N)]-1,2-C 2B 10H 10 (6) in 85% isolated yield. Complex 1 reacted with 3-(1-hexynyl)pyridine to afford α-C-H activation species Cp2Zr{η2-C,N-[5-(nBuCtC)C 5H 3NN]}(σ-C2B10H11) (8a) andCp2Zr{η2-C,N-[3-(nBuCtC)C 5H 3NN]}-(σ- C2B10H11) (8b) in a molar ratio of 42:58, as determined by the 1H NMR spectrum. In the presence of CuI, however, the CtC insertion products zirconacyclopentenes 1,2-[Cp2ZrC(2-C5H4N)dCR]-1,2-C 2B 10H 10 [R = Bun (9), Ph (10)] were obtained in 74-77% yields. It is suggested that the coordination of pyridine to the Zr atom is crucial for α-C-H activation (σ-bond metathesis). The presence of CuI can alter the reaction path by preventing the coordination of pyridine to the Zr atom, which blocks the α-C-H activation path, leading to the alkyne insertion reaction. All complexes were characterized by 1H, 13C, and 11B NMR spectra as well as elemental analyses. Their structures were further confirmed by single-crystal X-ray analyses. © 2011 American Chemical Society.

Zhou Q.-L.,Nankai University
Advanced Synthesis and Catalysis | Year: 2011

In 2000 China ranked 5th in the world (7.9%) in the publication of SCI papers on organic synthesis and catalysis; by 2008 China had become 1st (21.6%), followed by the USA, Germany and Japan. Major contributions made by Chinese research groups in the last decade in the areas of total synthesis of complex natural products, cross-coupling, asymmetric catalysis, and heterogeneous catalysis are highlighted. The output and quality of the research on synthesis and catalysis from China continue to increase, so that with the rapid development of China's economy, Chinese chemists will make greater contributions to organic synthesis and catalysis in the future. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Huang X.,Peking University | Jiao N.,Peking University | Jiao N.,Nankai University
Organic and Biomolecular Chemistry | Year: 2014

A novel and efficient approach to alkenyl nitriles from readily available propargylic alcohols has been developed. This nitrogenation reaction is transition-metal-free and could be conducted under air at ambient temperature, which makes this protocol promising and practical. Moreover, NH4Br is disclosed as an efficient additive to promote the stereoselectivity of this reaction. © the Partner Organisations 2014.

Yang N.,Beihang University | Yang N.,CAS Institute of Process Engineering | Zhai J.,Beihang University | Zhai J.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
ACS Nano | Year: 2010

As a novel two-dimensional (2D) material, graphene shows great benefits in electric and material science. Compared to 1D nanomaterials, it may show more excellent properties. Here, we introduced graphene as 2D bridges into the nanocrystalline electrodes of dye-sensitized solar cells, which brought a faster electron transport and a lower recombination, together with a higher light scattering. On the basis of these advantages, the short-circuit current density was increased by 45% without sacrificing the open-circuit voltage, and the total conversion efficiency was 6.97%, which was increased by 39%, comparing with the nanocrystalline titanium dioxide photoanode, and it was also much better than the 1D nanomaterial composite electrode. © 2010 American Chemical Society.

Zhang Z.,CNRS Paul Pascal Research Center | Zhang Z.,Nankai University | Grelet E.,CNRS Paul Pascal Research Center
Soft Matter | Year: 2013

Filamentous viruses of similar molecular and subunitary structure can form either a liquid crystalline nematic phase or a chiral nematic-also called cholesteric-phase, which is an elegant example of how self-organization of nanorods, with otherwise similar properties, can be affected by only subtle differences of surface properties and of the arrangement of the constituent subunits. In this work, we studied the influence of viral surface properties on the self-assembly of rod-like fd virus suspensions into the chiral nematic phase. For this purpose, the filamentous fd virus has been subjected to various chemical modifications on its capsid proteins: several organic molecules of different sizes and structures, including two popular fluorescent dyes (fluorescein and rhodamine), were coupled to the surface amino groups of the virus. The resulting chemically modified viruses still form a cholesteric phase in an aqueous suspension, but with a lower helicity compared to suspensions made of wild-type fd viruses. The degree of unwinding of the helical periodicity (or cholesteric pitch) depends on the structure of the labeled molecules. In addition, the chemically modified viruses exhibit a well-defined first order phase transition between the isotropic liquid and the liquid-crystalline state. Besides these modifications targeting the amino groups, the surface carboxyl groups were coupled with amino compounds so that the surface charge of fd viruses was reversed from negative to positive. The resulting particles can only form a nematic phase without any macroscopic helicity. These results suggest that inter-particle interactions, together with the intrinsic chirality of the virus, play an important role in the origin of the helical twist in the cholesteric phase. This journal is © 2013 The Royal Society of Chemistry.

Shan C.,Nankai University | Yai T.,Tokyo Institute of Technology
Habitat International | Year: 2011

The aim of this study is to provide an understanding of the legal requirements and implementation environment of public involvement (PI) in infrastructure planning processes at the national and local levels in China. China's transportation planning is examined to understand the infrastructure planning framework stipulated in the laws and regulations on city planning. The city planning ordinances of 27 provincial capitals and 4 municipalities directly under the Central Government are investigated and their requirements for PI are classified. Factors affecting PI requirements are considered including: geographic location, population and level of economic development among others. The authors discuss the effect of the social environment, geography, economic development level and legal requirements on PI implementation. Legislative and regulatory improvements concerning planning procedures and PI are suggested, with the advanced cities to be used as models. © 2010 Elsevier Ltd.

Perc M.,University of Maribor | Wang Z.,Nankai University
PLoS ONE | Year: 2010

To be the fittest is central to proliferation in evolutionary games. Individuals thus adopt the strategies of better performing players in the hope of successful reproduction. In structured populations the array of those that are eligible to act as strategy sources is bounded to the immediate neighbors of each individual. But which one of these strategy sources should potentially be copied? Previous research dealt with this question either by selecting the fittest or by selecting one player uniformly at random. Here we introduce a parameter u that interpolates between these two extreme options. Setting u equal to zero returns the random selection of the opponent, while positive u favor the fitter players. In addition, we divide the population into two groups. Players from group A select their opponents as dictated by the parameter u, while players from group B do so randomly irrespective of u. We denote the fraction of players contained in groups A and B by v and 1 - v, respectively. The two parameters u and v allow us to analyze in detail how aspirations in the context of the prisoner's dilemma game influence the evolution of cooperation. We find that for sufficiently positive values of u there exist a robust intermediate v≈0:5 for which cooperation thrives best. The robustness of this observation is tested against different levels of uncertainty in the strategy adoption process K and for different interaction networks. We also provide complete phase diagrams depicting the dependence of the impact of u and v for different values of K, and contrast the validity of our conclusions by means of an alternative model where individual aspiration levels are subject to evolution as well. Our study indicates that heterogeneity in aspirations may be key for the sustainability of cooperation in structured populations. © 2010 Perc, Wang.

Zhao J.,University of Science and Technology Beijing | Yang Q.,Nankai University
Inverse Problems in Science and Engineering | Year: 2013

In this article, we first introduce a simple but practical projection method for solving the multiple-sets split feasibility problem, which is to find a point in the intersection of a family of closed convex sets in one space, such that its image under a linear transformation is in the intersection of another family of closed convex sets in the image space. In each iteration of this method, the step-size is directly computed, and is shown to be the best for the current direction. Then we consider the corresponding relaxed projection scheme for the proposed method. The theoretical convergence results are established. Preliminary numerical experiments show that this simple method and its relaxed scheme are easy to implement and practical. © 2013 Copyright Taylor and Francis Group, LLC.

Xu S.,Xian Jiaotong University | He Z.,Nankai University
RSC Advances | Year: 2013

Organic synthetic reactions mediated by tertiary phosphines have attracted much attention in the organic chemistry community in the past two decades. These reactions can be divided into two categories: phosphine-catalyzed and stoichiometric phosphine-mediated transformations. While the phosphine-catalyzed reactions mechanistically rely on the unique properties of tertiary phosphines such as excellent nucleophilicity and good leaving group ability, the stoichiometric transformations are usually driven by nucleophilicity and strong oxyphilicity of tertiary phosphines. Since tertiary phosphines represent an important class of versatile chemical reagents in organic synthesis, stoichiometric phosphine-mediated reactions have recently demonstrated their uniqueness and high efficiency in organic synthesis, particularly with respect to the construction of carbon-carbon and carbon-heteroatom bonds, and therefore have stimulated much research interest. In this review, recent advances in stoichiometric phosphine-mediated reactions primarily including olefinations and annulations are summarized. © 2013 The Royal Society of Chemistry.

Du P.,Tianjin University | Wang X.,Tianjin University | Xu C.,Tianjin University | Gao Y.,Nankai University
Analytical Biochemistry | Year: 2012

The pseudo-amino acid composition has been widely used to convert complicated protein sequences with various lengths to fixed length digital feature vectors while keeping considerable sequence order information. However, so far the only software available to the public is the web server PseAAC (http://www.csbio.sjtu.edu.cn/bioinf/PseAAC), which has some limitations in dealing with large-scale datasets. Here, we propose a new cross-platform stand-alone software program, called PseAAC-Builder (http://www.pseb.sf.net), which can be used to generate various modes of Chou's pseudo-amino acid composition in a much more efficient and flexible way. It is anticipated that PseAAC-Builder may become a useful tool for studying various protein attributes. © 2012 Elsevier Inc. All rights reserved.

The energy E of a graph G is equal to the sum of the absolute values of the eigenvalues of G. In 2005 Lin et al. determined the trees with a given maximum vertex degree △ and maximum E, that happen to be trees with a single vertex of degree △. Later, in 2009 Li et al. characterized the maximum energy trees having two vertices of maximum degree △. In this paper we consider the general case and characterize the maximum energy trees with one maximum degree vertex and another second maximum degree vertex.

Clarke C.P.,Nankai University
Program | Year: 2012

Purpose: This paper aims to examine the experiences of new users of Second Life in order to identify potential barriers and attractors to the expansion of the userbase and therefore the market for in-world information services. Design/methodology/approach: A multi-faceted methodological approach was taken utilising two questionnaires (pre- and post-immersion), non-participant overt observation, structured interviews, and online diary keeping. Data was then analysed to identify barriers and attractors. Findings: More negative experiences were recorded than positive, with the costs, time commitment, stigma of using, the lack of structure, social interaction, and the complexity of the control interface all provoking negative responses. Avatar creation, and the creativity and quality of graphical presentation produced positive responses. Research limitations/implications: Due to the investment in time required to participate in the research, the sample size is smaller than ideal thus limiting the conclusions that can be generalised. The research also did not directly include interaction with online library or information services. Practical implications: For librarians using SL the research demonstrates that the response from new users is less than enthusiastic and that when designing virtual library services care should be taken to avoid the barriers identified here and to focus on the features found attractive by participants. Originality/value: Previous studies have examined the implementation of in-world information services without examining the experience of new users. Those studies that have looked directly at the user's interaction with virtual worlds are more focused on MMORPGs and on current users. © Emerald Group Publishing Limited.

Yan F.,Nankai University
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2012

In order to study the microorganisms on the surface of the ancient stones in Yungang Grottoes and nearby rock samples, a rapid microbial detection assay was designed. The microbial community composition from the rock samples of the Yungang Grottoes and nearby was analyzed by PCR-DGGE. According to the phylogenetic analysis, the microbes from the rock samples of Yungang Grottoes were divided into four groups: Gamma-proteobacteria, Sphingobacteria, Alpha-proteobacter and Actinobacteria. By aligning the sequencing results in GenBank, Gamma-proteobacteria, Firmicutes and Alpha-proteobacter were found in the rock samples near Yungang Grottoes. Our research successfully detected the microbial community composition on the surface of the rock samples in and near the Yungang Grottoes, which brought us significant theoretical basis for the future protection of the Yungang Grottoes. We also proved that the combination of DGGE and molecular cloning was a useful, rapid and accurate method for detecting the microbial community composition on stone relics.

In order to investigate the regulatory mechanisms of Mortierella alpina desaturase genes by low temperature and exogenous unsaturated fatty acids (UFAs) at the transcriptional level. We performed time-course studies of fatty acid desaturase gene expression by real-time PCR and determined fatty acid desaturase gene promoter activity using promoter-reporter constructs. Relative expression results in real-time PCR showed that the mRNA levels of three fatty acid desaturase genes (Fad6, Fad12 and Fad3) were rapidly and transiently enhanced after 1 h of shifting to low temperature, in contrast, high concentration of exogenous oleic acid (OA) which was a monounsaturated fatty acid containing a D9 double bond suppressed the transcription of these genes and the transcriptional response appeared to be rapid and transient. Also, there was no absolute correlation between mRNA abundance and production of corresponding fatty acids. The pFAD6 promoter activity was induced by low temperature in a time-dependent manner and reduced in a dose- and time-dependent manner by addition of UFAs to the media, and alpha-linolenic acid (ALA) containing three double bonds appeared to have a more effective inhibition than linoleic acid (LA) and OA. These results indicate that there may be post-transcriptional control and other modes of regulation of UFAs synthesis in M. alpina when facing different stimuli such as low temperature and exogenous unsaturated fatty acids besides the regulation in the transcription of fatty acid desaturase genes at the initial stage. Also, there may be an unknown end-product (changes in fatty acid compositions) feedback regulation in the transcription of fatty acid desaturase genes to maintain cellular UFAs' homeostasis. In a word, we assessed mechanisms of transcriptional regulation in M. alpina fatty acid desaturase gene expression for the first time and we wish to make it possible to obtain a better understanding of the mechanisms and get some theoretical knowledge to offer some guidance to the industrial production of UFAs by transgenic technology and microbial fermentation technology.

Kehl T.,German Cancer Research Center | Tan J.,Nankai University | Materniak M.,National Veterinary Research Institute
Viruses | Year: 2013

Within the field of retrovirus, our knowledge of foamy viruses (FV) is still limited. Their unique replication strategy and mechanism of viral persistency needs further research to gain understanding of the virus-host interactions, especially in the light of the recent findings suggesting their ancient origin and long co-evolution with their nonhuman hosts. Unquestionably, the most studied member is the primate/prototype foamy virus (PFV) which was originally isolated from a human (designated as human foamy virus, HFV), but later identified as chimpanzee origin; phylogenetic analysis clearly places it among other Old World primates. Additionally, the study of non-simian animal FVs can contribute to a deeper understanding of FV-host interactions and development of other animal models. The review aims at highlighting areas of special interest regarding the structure, biology, virus-host interactions and interspecies transmission potential of primate as well as non-primate foamy viruses for gaining new insights into FV biology. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Zuo Z.,Nankai University
Plant physiology and biochemistry : PPB / Société française de physiologie végétale | Year: 2012

Acetic acid widely spreads in atmosphere, aquatic ecosystems containing residues and anoxic soil. It can inhibit aquatic plant germination and growth, and even cause programmed cell death (PCD) of yeast. In the present study, biochemical and physiological responses of the model unicellular green algae Chlamydomonas reinhardtii were examined after acetic acid stress. H(2)O(2) burst was found in C. reinhardtii after acetic acid stress at pH 5.0 for 10 min. The photosynthetic pigments were degraded, gross photosynthesis and respiration were disappeared gradually, and DNA fragmentation was also detected. Those results indicated that C. reinhardtii cells underwent a PCD but not a necrotic, accidental cell death event. It was noticed that C. reinhardtii cells in PCD released abundant volatile organic compounds (VOCs) upon acetic acid stress. Therefore, we analyzed the VOCs and tested their effects on other normal cells. The treatment of C. reinhardtii cultures with VOCs reduced the cell density and increased antioxidant enzyme activity. Therefore, a function of VOCs as infochemicals involved in cell-to-cell communication at the conditions of applied stress is suggested. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Mao X.,University of Georgia | Zhang H.,University of Georgia | Zhang H.,Nankai University | Yin Y.,University of Georgia | And 2 more authors.
Nucleic Acids Research | Year: 2012

The majority of bacterial genes are located on the leading strand, and the percentage of such genes has a large variation across different bacteria. Although some explanations have been proposed, these are at most partial explanations as they cover only small percentages of the genes and do not even consider the ones biased toward the lagging strand. We have carried out a computational study on 725 bacterial genomes, aiming to elucidate other factors that may have influenced the strand location of genes in a bacterium. Our analyses suggest that (i) genes of some functional categories such as ribosome have higher preferences to be on the leading strands; (ii) genes of some functional categories such as transcription factor have higher preferences on the lagging strands; (iii) there is a balancing force that tends to keep genes from all moving to the leading and more efficient strand and (iv) the percentage of leading-strand genes in an bacterium can be accurately explained based on the numbers of genes in the functional categories outlined in (i) and (ii), genome size and gene density, indicating that these numbers implicitly contain the information about the percentage of genes on the leading versus lagging strand in a genome. © 2012 The Author(s).

This article defines information inequality as multifaceted disparity between individuals, communities or nations in mobilizing society's information resources for the benefit of their lives and development. It then examines related research from a wide range of disciplines that focuses either on information inequality in general or on its specific forms, e.g. information poverty, information divide, knowledge gap and digital divide. It shows that it is possible to identify a number of clusters of information inequality research according to their theoretical perspectives, and that these perspectives have inherited to a great extent the traditional divisions of social sciences between structure vs agency, society vs individuals and objectivism vs subjectivism. Following earlier calls for greater dialogue between divisions of related research, this article goes further to call for integrative theorizing of information inequality in the way exemplified by Bourdieu's research on social inequality. © 2011 Chartered Institute of Library and Information Professionals.

Zhao L.,Nankai University
Advanced Nonlinear Studies | Year: 2016

In [5], Ortega has analyzed "generalized" collision solutions of the periodically forced rectilinear Kepler problem. In this note, we explain a different approach to study these solutions by embedding the nonautonomous Hamiltonian system into the zero-energy level of an autonomous Hamiltonian system and by employing the Levi-Civita regularization to regularize the double collisions. In addition to this, under a certain smoothness hypothesis of the periodic force term, we show that there exists a set of positive measure of generalized quasi-periodic solutions in the extended phase space, each of them accumulated by generalized periodic solutions of the system. The energy of these quasi-periodic solutions can have an arbitrary large absolute value. © 2016 by De Gruyter.

Gao G.,Harvard University | Gao G.,Nankai University | Vecitis C.D.,Harvard University
ACS Applied Materials and Interfaces | Year: 2012

Three-dimensional porous electrodes often suffer from diffusional mass-transfer limitations that may be overcome by having the target solution flow through the electrode. Here, we examine the reactive depth and performance of an electrochemical carbon nanotube (CNT) network toward phenol removal and oxidation in the batch and flow configurations where mass transport into the CNT network is predominantly via diffusion and convection, respectively. Scanning electron microscopy depth profile imaging of phenol electropolymerization is used as a direct probe of the reactive depth. In the batch case, electropolymerization is observed to be greatest at the network surface nearest the cathode and decreases linearly to near zero at a depth of 25 μm. In stark contrast, electropolymerization is observed to be independent of the depth in the flow configuration. In agreement with the depth profile results, phenol removal is increased up to 10-fold, the current efficiency is increased by at least 2-fold, and susceptibility toward passivation is reduced in the flow versus batch configuration. Thus, the enhanced electrochemical performance in the flow configuration is partially due to the convective "activation" of the internal CNT network electron-transfer sites that are diffusion-inaccessible. © 2012 American Chemical Society.

Qi X.,Nankai University | Watanabe M.,Tohoku University | Aida T.M.,Tohoku University | Smith R.L.,Tohoku University
Bioresource Technology | Year: 2012

A method for converting glucose into 5-hydroxymethylfurfural (5-HMF) without using chromium-containing catalysts was developed. The method uses ionic liquid-water mixtures with a ZrO 2 catalyst. Addition of a certain amount of water (10-50wt.%) into the 1,3-dialkylimidazolium chloride ionic liquid promoted the formation of 5-HMF from glucose compared with that in either pure water or in the pure ionic liquid. A 5-HMF yield of 53% was obtained within 10min at 200°C in a 50:50w/w% 1-hexyl-3-methyl imidazolium chloride-water mixture in the presence of ZrO 2. The 1,3-dialkylimidazolium ionic liquids having Cl - or HSO4- anions were effective for promoting 5-HMF formation. Addition of protic solvents such as methanol and ethanol to the ionic liquid had a similar synergistic effect as water and promoted fructose and 5-HMF formation. The results reported in this work can be extended to other fields, where the ratio of ionic liquid and protic solvent can be adjusted to promote the desired reactions. © 2012 Elsevier Ltd.

Liao Y.,Nankai University | Liao Y.,University of Heidelberg | Liao Y.,Peking University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

When the standard model is viewed as a low energy effective theory, the neutrinos can obtain mass from higher dimensional operators. It has been known for long that such an operator first appears at mass dimension five and that it is unique. Here we show that the effective neutrino mass operator at every higher dimension is unique. This general claim is established using Young tableau, and illustrated by exhausting all potentially different operators at dimension seven. The result is relevant to the search of new physics effects beyond neutrino mass that can arise at a relatively low energy scale. © 2010 Elsevier B.V.

He L.,Singapore University of Technology and Design | Pan J.,University of Victoria | Xu J.,Nankai University
IEEE Transactions on Mobile Computing | Year: 2013

The introduction of mobile elements has created a new dimension to reduce and balance the energy consumption in wireless sensor networks. However, data collection latency may become higher due to the relatively slow travel speed of mobile elements. Thus, the scheduling of mobile elements, i.e., how they traverse through the sensing field and when they collect data from which sensor, is of ultimate importance and has attracted increasing attention from the research community. Formulated as the traveling salesman problem with neighborhoods (TSPN) and due to its NP-hardness, so far only approximation and heuristic algorithms have appeared in the literature, but the former only have theoretical value now due to their large approximation factors. In this paper, following a progressive optimization approach, we first propose a combine-skip-substitute (CSS) scheme, which is shown to be able to obtain solutions within a small range of the lower bound of the optimal solution. We then take the realistic multirate features of wireless communications into account, which have been ignored by most existing work, to further reduce the data collection latency with the multirate CSS (MR-CSS) scheme. Besides the correctness proof and performance analysis of the proposed schemes, we also show their efficiency and potentials for further extensions through extensive simulation. © 2002-2012 IEEE.

Pan G.,Soochow University of China | Guo Q.,Soochow University of China | Ma Y.,Nankai University | Yang H.,Soochow University of China | Li B.,Soochow University of China
Angewandte Chemie - International Edition | Year: 2013

The efficient promotion of cell adhesion on a polymer surface and detachment of sheets of cells is possible with thermo-responsive cell culture substrates that are biofunctionalized through noncovalent molecular imprinting. The key is the thermo-responsive "specific binding" of the cell-adhesive peptide RGDS on the cell sheet harvest system (see picture). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu J.,Northeast Normal University | Fang Z.,Northeast Normal University | Zhang Q.,Northeast Normal University | Liu Q.,Northeast Normal University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

Ag2CO3 is the key: The transition-metal-catalyzed cycloaddition of isocyanides and unactivated terminal alkynes has been realized with Ag2CO3 as a unique and robust catalyst (see scheme). The protocol is highly efficient, allowing a broad range of terminal and internal alkynes to react under base- and ligand-free conditions, generating synthetically useful oligosubstituted pyrroles in high yields. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Changes of neural oscillations at a variety of physiological rhythms are effectively associated with cognitive performance. The present study investigated whether the directional indices of neural information flow (NIF) could be used to symbolize the synaptic plasticity impairment in hippocampal CA3-CA1 network in a rat model of melamine. Male Wistar rats were employed while melamine was administered at a dose of 300 mg/kg/day for 4 weeks. Behavior was measured by the Morris water maze(MWM)test. Local field potentials (LFPs) were recorded before long-term potentiation (LTP) induction. Generalized partial directed coherence (gPDC) and phase-amplitude coupling conditional mutual information (PAC_CMI) were used to measure the unidirectional indices in both theta and low gamma oscillations (LG, ~ 30-50 Hz). Our results showed that melamine induced the cognition deficits consistent with the reduced LTP in CA1 area. Phase locking values (PLVs) showed that the synchronization between CA3 and CA1 in both theta and LG rhythms was reduced by melamine. In both theta and LG rhythms, unidirectional indices were significantly decreased in melamine treated rats while a similar variation trend was observed in LTP reduction, implying that the effects of melamine on cognitive impairment were possibly mediated via profound alterations of NIF on CA3-CA1 pathway in hippocampus. The results suggested that LFPs activities at these rhythms were most likely involved in determining the alterations of information flow in the hippocampal CA3-CA1 network, which might be associated with the alteration of synaptic transmission to some extent.

Zhang L.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University | Guan X.,Northeast Normal University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2013

Aldehyde Termination: A novel copper-catalyzed transformation from methyl ketones into aldehydes has been accomplished. This method is applicable to a wide range of aromatic and aliphatic methyl ketones and chemoselectively produces aldehydes, accompanied by the release of hydrogen (H2) and carbon dioxide (CO2) as by-products. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Huang P.,Sun Yat Sen University | Yuan F.-F.,Nankai University
Physics of the Dark Universe | Year: 2016

Following the spirit of the equivalence principle, we take a step further to recognize the free fall of the observer as a method to eliminate causes that would lead the perceived vacuum to change its original state. Thus, it is expected that the vacuum should be in a rigid Minkowski state or be uniformly expanding. By carefully investigating the impact on measurement caused by the expansion, we clarify the exact meaning of the uniformly expanding vacuum and find that this proposal may be able to explain the current observations of an accelerating universe. © 2016 Elsevier B.V.

Zhou X.-F.,Nankai University | Zhou X.-F.,State University of New York at Stony Brook | Oganov A.R.,State University of New York at Stony Brook | Oganov A.R.,Moscow State University | And 2 more authors.
Physical Review Letters | Year: 2012

The energy landscape of Mg(BH4)2 under pressure is explored by ab initio evolutionary calculations. Two new tetragonal structures, with space groups P4Â̄ and I41/acd, are predicted to be lower in enthalpy by 15.4 and 21.2kJ/mol, respectively, than the earlier proposed P42nm phase. We have simulated x-ray diffraction spectra, lattice dynamics, and equations of state of these phases. The density, volume contraction, bulk modulus, and simulated x-ray diffraction patterns of I4 1/acd and P4Â̄ structures are in excellent agreement with the experimental results. © 2012 American Physical Society.

Tong M.-C.,Wuhan University | Chen X.,Wuhan University | Tao H.-Y.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Angewandte Chemie - International Edition | Year: 2013

Ylides at a crossing: An unprecedented 1,3-dipolar cycloaddition (cross-cycloaddition) between two different ylides (see scheme) was realized by using the chiral CuI/tBu-Phosferrox complex as the catalyst under mild reaction conditions. This catalytic system provides an expeditious approach to the construction of highly functionalized 1,2,4-triazinane derivatives in good yields with excellent diastereoselectivities and enantioselectivities. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

He Z.-L.,Wuhan University | Teng H.-L.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Angewandte Chemie - International Edition | Year: 2013

As easy as π: Fulvenes serve as 6π dipolarophiles in the title reaction in the presence of the chiral CuI/(S)-L complex. The present system provides a unique and straightforward access to enantioenriched, highly functionalized piperidine derivatives in good yields and excellent diastereoselectivities and enantioselectivities. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xu X.,Nankai University | Xu X.,University of California at Los Angeles | Liu P.,University of California at Los Angeles | Lesser A.,Stanford University | And 3 more authors.
Journal of the American Chemical Society | Year: 2012

The first theoretical study on the effects of ligands on the mechanism, reactivities, and regioselectivities of Rh(I)-catalyzed (5 + 2) cycloadditions of vinylcyclopropanes (VCPs) and alkynes has been performed using density functional theory (DFT) calculations. Highly efficient and selective intermolecular (5 + 2) cycloadditions of VCPs and alkynes have been achieved recently using two novel rhodium catalysts, [Rh(dnCOT)] +SbF 6 - and [Rh(COD)] +SbF 6 -, which provide superior reactivities and regioselectivities relative to that of the previously reported [Rh(CO) 2Cl] 2 catalyst. Computationally, the high reactivities of the dnCOT and COD ligands are attributed to the steric repulsions that destabilize the Rh-product complex, the catalyst resting state in the catalytic cycle. The regioselectivities of reactions with various alkynes and different Rh catalysts are investigated, and a predictive model is provided that describes substrate-substrate and ligand-substrate steric repulsions, electronic effects, and noncovalent π/π and C-H/π interactions. In the reactions with dnCOT or COD ligands, the first new C-C bond is formed proximal to the bulky substituent on the alkyne to avoid ligand-substrate steric repulsions. This regioselectivity is reversed either by employing the smaller [Rh(CO) 2Cl] 2 catalyst to diminish the ligand-substrate repulsions or by using aryl alkynes, for which the ligand-substrate interactions become stabilizing due to π/π and C-H/π dispersion interactions. Electron-withdrawing groups on the alkyne prefer to be proximal to the first new C-C bond to maximize metal-substrate back-bonding interactions. These steric, electronic, and dispersion effects can all be utilized in designing new ligands to provide regiochemical control over product formation with high selectivities. The computational studies reveal the potential of employing the dnCOT family of ligands to achieve unique regiochemical control due to the steric influences and dispersion interactions associated with the rigid aryl substituents on the ligand. © 2012 American Chemical Society.

Zhang D.G.,Nanyang Technological University | Moh K.J.,Nanyang Technological University | Yuan X.-C.,Nankai University
Optics Express | Year: 2010

Surface plasmon-coupled emission from shaped PMMA films doped with randomly oriented fluorescence molecules was investigated. Experimental results show that for different shapes, such as triangle or circular structures, the SPCE ring displays different intensity patterns. For a given shape, it was observed that the relative position and polarization of an incident laser spot on the shaped PMMA can be used to adjust the fluorescence intensity distribution of the SPCE ring. The proposed method enables controlling the fluorescence emission in azimuthal direction in addition to the radial angle controlled by common SPCE, which will further enhances the fluorescence collection efficiency and has applications in fluorescence sensing, imaging and so on. © 2010 Optical Society of America.

Zhao L.,Nankai University
Communications in Theoretical Physics | Year: 2010

Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity. Though this is a beautiful idea, which may resolve many long standing problems in the theories of gravity, it also raises many other problems. In this article I will comment on some of the problems ofVerlinde's proposal with special emphasis on the thermodynamical origin of the principle of relativity. It is found that there is a large group of hidden symmetries of thermodynamics, which contains the Poincare group of the spacetime for which space is emergent. This explains the thermodynamic origin of the principle of relativity. © Chinese Physical Society and IOP Publishing Ltd.

Chitambar M.,University of Michigan | Wang Z.,University of Michigan | Liu Y.,Nankai University | Rockett A.,Urbana University | Maldonado S.,University of Michigan
Journal of the American Chemical Society | Year: 2012

The steady-state photoelectrochemical responses of p-GaP photoelectrodes immersed in aqueous electrolytes and sensitized separately by six triphenylmethane dyes (rose bengal, rhodamine B, crystal violet, ethyl violet, fast green fcf, and brilliant green) have been analyzed. Impedance measurements indicated that these p-GaP(100) photoelectrodes operated under depletion conditions with an electric field of ∼8.5 × 10 5 V cm -1 at the p-GaP/solution interface. The set of collected wavelength-dependent quantum yield responses were consistent with sensitization occurring specifically from adsorbed triphenylmethane dyes. At high concentrations of dissolved dye, the measured steady-state photocurrent- potential responses collected at sub-bandgap wavelengths suggested unexpectedly high (>0.1) net internal quantum yields for sensitized hole injection. Separate measurements performed with rose bengal adsorbed on p-GaP surfaces pretreated with (NH 4) 2S verified efficient sensitized hole injection. A modified version of wxAMPS, a finite-difference software package, was utilized to assess key operational features of the sensitized p-GaP photocathodes. The net analysis showed that the high internal quantum yield values inferred from the experimental data were most likely afforded by the internal electric field present within p-GaP, effectively sweeping injected holes away from the interface and minimizing their participation in deleterious pathways that could limit the net collection yield. These simulations defined effective threshold values for the charge carrier mobilities (≥10 -6 cm 2 V -1 s -1 and ≥10 -1 cm 2 V -1 s -1 at dopant densities of 10 18 and 10 13 cm -3, respectively), hole injection rate constants (≥10 12 s -1), and surface trap densities (10 12 cm -2) needed to attain efficient hole collection with the quality of p-GaP materials used here. The cumulative experimental and modeling data thus provide insight on design strategies for assembling new types of dye-sensitized photocathodes that operate under depletion conditions. © 2012 American Chemical Society.

Du S.-Y.,CAS Institute of Physics | Du S.-Y.,Nankai University | Li Z.-Y.,CAS Institute of Physics
Optics Letters | Year: 2010

We propose a scheme to enhance near-UVband absorption of a rutile TiO 2 nanoparticle by placing Au nanoparticles in its neighborhood. The discrete-dipole approximation method was employed to calculate the absorption spectrum of pure rutile TiO2 and that of TiO2 mixed with Au nanoparticles. The results indicate that pure rutile TiO2 has its maximum absorption located in the deep-UV band. With the existence of Au nanoparticles, a significant light harvesting effect occurs, and this maximum shifts to the near-UV band, where usual excitation wavelength falls. © 2010 Optical Society of America.

In the elementary scattering of surface plasmon polaritons (SPPs) at individual subwavelength (sub-λ) objects on metallic surfaces, the in-plane transmission and reflection of SPPs are shown to be two related scattering processes and to satisfy some novel symmetry relations, provided that the objects are mirror symmetric and are narrow enough (<0.1λ approximately). To interpret these symmetry relations, a new generalized symmetry principle for the scattered field is put forward, which is much less limited than the classical one and is shown to have wide applications for other sub-λ scattering problems. © 2010 Optical Society of America.

He Y.,Hubei University | Yan X.,Nankai University
Science China Chemistry | Year: 2011

Mn-doped ZnS quantum dots /methyl violet nanohybrids were explored to develop a novel room temperature phosphorescence (RTP) sensor for the detection of DNA. Methyl violet (MV) as the electron acceptors was adsorbed on the surface of the quantum dots (QDs) to quench the RTP of the Mn-doped ZnS QDs through an electron-transfer process under excitation. The addition of DNA recovered the RTP signal of the Mn-doped ZnS QDs due to the binding of MV with DNA and the removal of MV from the surface of the Mn-doped ZnS QDs. Under the optimal conditions, the enhanced RTP intensity of the Mn-doped ZnS QDs/MV nanohybrids linearly increased with the concentration of DNA from 0.08 to 12 mg L -1 with the detection limit of 33.6 μg L-1. The relative standard deviation for eleven replicate detections of the reagent blank was 3.7%. The developed method was applied to the detection of DNA in spiked urine samples with recoveries of 96%-103% without interference from nonspecific fluorescence. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Zhou J.,China Institute of Technology | Wan X.,China Institute of Technology | Liu Y.,China Institute of Technology | Zuo Y.,China Institute of Technology | And 7 more authors.
Journal of the American Chemical Society | Year: 2012

Small molecules, namely, DCAO 3TBDT and DR 3TBDT, with 2-ethylhexoxy substituted BDT as the central building block and octyl cyanoacetate and 3-ethylrhodanine as different terminal units with the same linkage of dioctyltertthiophene, have been designed and synthesized. The photovoltaic properties of these two molecules as donors and fullerene derivatives as the acceptors in bulk heterojunction solar cells are studied. Among them, DR 3TBDT shows excellent photovoltaic performance, and power conversion efficiency as high as 7.38% (certified 7.10%) under AM 1.5G irradiation (100 mW cm -2) has been achieved using the simple solution spin-coating fabrication process, which is the highest efficiency reported to date for any small-molecule-based solar cells. The results demonstrate that structure fine turning could cause significant performance difference and with that the performance of solution-processed small-molecule solar cells can indeed be comparable with or even surpass their polymer counterparts. © 2012 American Chemical Society.

Wang B.,Institute of Materials Research and Engineering of Singapore | Zhang X.,Wuhan University | Garcia-Vidal F.J.,Autonomous University of Madrid | Yuan X.,Nankai University | Teng J.,Institute of Materials Research and Engineering of Singapore
Physical Review Letters | Year: 2012

Here we investigate theoretically and numerically the coupling between surface plasmon polaritons (SPPs) in monolayer graphene sheet arrays that have a period much smaller than the wavelength. We show that when the collective SPP is excited with an out-of-phase illumination, the beam tends to propagate toward the opposite direction of the Bloch momentum, reflecting a negative coupling between the constituent SPPs. In contrast, for in-phase illumination, the incident beam is split into two collective SPPs that are highly collimated and display low propagation loss. Moreover, the coupling between the individual SPPs results in a reduction of the modal wavelength of the SPP in comparison with that of a single graphene sheet. © 2012 American Physical Society.

Ke H.-W.,Tianjin University | Li X.-Q.,Nankai University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

Since the discovery of X(3872), its structure has been in ceaseless dispute. The data of X(3872)→π +π -π0J/ψ suggest that X(3872) may be a high-spin charmoniumlike particle of 2 -+. In terms of the light-front quark model we calculate the rates of the radiative decays X(3872)→J/ψ(ψ ′) γ supposing X(3872) to be a 2 -+ charmonium. Within this framework, our theoretical prediction on BR(X(3872)→ψ(1S)γ) is at order of 10 -3 which is slightly lower than the BABAR Collaboration's data but close to the Belle Collaboration's. Our prediction on BR(X(3872)→ψ ′γ) is at order of 10 -5 if ψ ′ is a pure 2S state or 10 -4 if ψ ′ is a 2S-1D mixture, which does not conflict with the upper bound set by Belle, but is much lower than BABAR's data. Thus if the future measurement decides the branching ratio of BR(X(3872) →ψ ′γ) to be much larger than 10 -4, the 2 -+ assignment for X(3872) should be ruled out. © 2011 American Physical Society.

Yao K.,Tsinghua University | Chen X.,Nankai University
Journal of Intelligent and Fuzzy Systems | Year: 2013

Uncertain differential equation is a type of differential equation driven by canonical process. In this paper, a concept of α-path to uncertain differential equation is first introduced, which is a type of deterministic function that solves an associate ordinary differential equation. Then, a numerical method is designed for solving uncertain differential equations, which essentially solves each α-path and produces an inverse uncertainty distribution of the solution. To illustrate the efficiency of the numerical method, several examples are given. © 2013 - IOS Press and the authors. All rights reserved.

Nanomaterials have been studied widely as the supporting materials for enzyme immobilization. However, the interactions between enzymes and carbon nanotubes (CNT) with different morphologies and surface functionalities may vary, hence influencing activities of the immobilized enzyme. To date how the adsorption mechanisms affect the activities of immobilized enzyme is not well understood. In this study the adsorption of catalase (CAT) on pristine single-walled carbon nanotubes (SWNT), oxidized single-walled carbon nanotubes (O-SWNT), and multi-walled carbon nanotubes (MWNT) was investigated. The adsorbed enzyme activities decreased in the order of O-SWNT>SWNT>MWNT. Fourier transforms infrared spectroscopy (FTIR) and circular dichrois (CD) analyses reveal more significant loss of α-helix and β-sheet of MWNT-adsorbed than SWNT-adsorbed CAT. The difference in enzyme activities between MWNT-adsorbed and SWNT-adsorbed CAT indicates that the curvature of surface plays an important role in the activity of immobilized enzyme. Interestingly, an increase of β-sheet content was observed for CAT adsorbed to O-SWNT. This is likely because as opposed to SWNT and MWNT, O-SWNT binds CAT largely via hydrogen bonding and such interaction allows the CAT molecule to maintain the rigidity of enzyme structure and thus the biological function. Copyright © 2013 Elsevier B.V. All rights reserved.

Liu Y.-L.,East China Normal University | Zhou J.,East China Normal University | Zhou J.,Nankai University
Chemical Communications | Year: 2012

We report the first example of highly enantioselective organocatalytic synthesis of 3-difluoroalkyl substituted 3-hydroxyoxindoles. The total synthesis of the difluoro analogue of convolutamydine E was achieved by this method. © 2012 The Royal Society of Chemistry.

Liu X.,Zhejiang University | Chen W.,Zhejiang University | Chen W.,Nankai University
Dalton Transactions | Year: 2012

A family of hexa-coordinated ruthenium(ii) complexes of bis(N-pyridylimidazolylidenyl)methane (l) were prepared and structurally characterized. Carbene transfer reactions of [Ru(p-cymene)Cl 2] 2, [Ru(CO) 2Cl 2] n and RuHCl(CO)(PPh 3) 3 with silver-NHC complexes in situ generated from [H 2L](PF 6) 2 and Ag 2O afforded [RuL(CH 3CN) 2](PF 6) 2 (1), [Ru 2L(p-cymene) 2Cl 2](PF 6) 2 (2), [RuL(CO) 2](PF 6) 2 (3) and [RuL(PPh 3) 2](PF 6) 2 (4), respectively. The reactions of 1 towards several N- and P-donors were studied. The treatment of 1 with 1,10-phenanthroline resulted in the substitution of one pyridine and one acetonitrile molecule affording [RuL(phen)(CH 3CN)](PF 6) 2 (5) as a mixture of two isomers. Reaction of 1,2-bis(diphenylphosphino)ethane (dppe) and 1 gave [RuL(dppe)(CH 3CN) 2](PF 6) 2 (7), in which two pyridines were substituted by a dppe ligand trans to two NHC groups. In contrast, reactions of 1 with ethane-1,2-diamine, propane-1,3-diamine and 3,5-dimethyl-1H-pyrazole led to the substitution of acetonitrile and subsequent N-H addition of the CN bond of the coordinated acetonitrile yielding [RuL(ethane-1,2-diamine)(N-(2-aminoethyl)acetimidamide)](PF 6) 2 (8), [RuL(propane-1,3-diamine)(N-(3-aminopropyl)acetimidamide)] (PF 6) 2 (9) and RuL(1-(3,5-dimethyl-1H-pyrazol-1-yl) ethanimine)(CH 3CN)](PF 6) 2 (10), respectively. © 2012 The Royal Society of Chemistry.

As an emerging new polymerization technique, controlled/"living" radical precipitation polymerization (CRPP) involves the introduction of controlled/"living" radical polymerization (CRP) mechanism into the precipitation polymerization system and can be effectively implemented by simply replacing the initiator normally used in the traditional precipitation polymerization (e.g., azobisisobutyronitrile (AIBN)) with a CRP initiating system. It combines the advantages of the traditional precipitation polymerization and CRP and can thus be performed in a controlled manner without need for any surfactant and stabilizer, leading to the precise control over the sizes, compositions, surface functionalities, and "living" groups of the resulting polymer microspheres. Several CRPP approaches have been developed up to now, including atom transfer radical precipitation polymerization (ATRPP), iniferter-induced "living" radical precipitation polymerization (ILRPP), and reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization (RAFTPP). In this feature article, we provide a detailed overview of these recently developed CRPP approaches and demonstrate their high versatility in the design and synthesis of advanced functional polymers such as uniform, highly crosslinked, and "living" functional polymer microspheres and advanced molecularly imprinted polymers (MIPs) including MIP microspheres with improved binding properties, water-compatible MIP microspheres, and MIP microspheres with stimuli-responsive template binding properties in aqueous media. In addition, some perspectives on this new research area are also presented. © 2013 Elsevier Ltd. All rights reserved.

Chen J.-T.,Nankai University
Journal of Medicinal Chemistry | Year: 2013

A series of conjugated hyaluronic acid particles (HAP), composed of a hydrophobic anticancer drug core and hydrophilic cyclodextrin/hyaluronic acid shell, were prepared through self-assembling and characterized by 1H NMR titration, electron microscopy, zeta potential, and dynamic light-scattering experiments. The nanometer-sized HAP thus prepared was biocompatible and biodegradable and was well-recognized by the hyaluronic acid receptors overexpressed on the surface of cancer cells, which enabled us to exploit HAP as an efficient targeted delivery system for anticancer drugs. Indeed, HAP exhibited anticancer activities comparable to the commercial anticancer drug cisplatin but with lower side effects both in vitro and in vivo. © 2013 American Chemical Society.

Wei C.,Shandong Agricultural University | Zhou H.,Nankai University | Zhou J.,Shandong Agricultural University
Talanta | Year: 2011

An ultrathin molecularly imprinted polymer film was anchored on an Au surface for fabricating a surface plasmon resonance sensor sensitive to acephate by a surface-bound photo-radical initiator. The polymerization in the presence of acephate resulted in a molecular-imprinted matrix for the enhanced binding of acephate. Analysis of the SPR wavenumber changes in the presence of different concentrations of acephate gave a calibration curve that included the ultrasensitive detection of acephate by the imprinted sites in the composite, Kass for the association of acephate to the imprinted sites, 7.7 × 1012 M-1. The imprinted ultrathin film revealed impressive selectivity. The selectivity efficiencies for acephate and other structurally related analogues were 1.0 and 0.11-0.37, respectively. Based on a signal to noise ratio of 3, the detection limits were 1.14 × 10 -13 M for apple sample and 4.29 × 10-14 M for cole sample. The method showed good recoveries and precision for the apple and cole samples spiked with acephate solution. This suggests that a combination of SPR sensing with MIP film is a promising alternative method for the detection of organophosphate compounds. © 2010 Elsevier B.V. All rights reserved.

Fang X.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Chemical Communications | Year: 2014

Organocatalysis has proven to be one of the most rapidly developing and competitive research areas in asymmetric catalysis since 2000, and has become a third branch besides biocatalysis and transition metal catalysis. In this feature article, recent progress from our research group on asymmetric organocatalysis, focusing on fine-tunable amine-thiourea catalysis, is described. Design of novel bifunctional amine-thiourea organocatalysts based upon the synergistic activation strategy via multiple hydrogen bonds and their applications in asymmetric C-C, C-N, and C-S bond-forming reactions under mild conditions are discussed in detail. The most attractive feature of the newly designed fine-tunable amine-thiourea catalysts is the incorporation of multiple hydrogen bonding donors and stereogenic centers. This journal is © The Royal Society of Chemistry.

Zheng Q.,Tsinghua University | Hua R.,Tsinghua University | Hua R.,Nankai University
Tetrahedron Letters | Year: 2010

1,3-Butadiynes underwent inter- and intramolecular double hydroamination with primary amines in the presence of CuCl at 100°C to afford 1,2,5-trisubsituted pyrroles in good to high yields. © 2010 Elsevier Ltd. All rights reserved.

Shi H.,The New School | Chertow M.,The New School | Song Y.,Nankai University
Journal of Cleaner Production | Year: 2010

To address the pollution that accompanies rapid industrial growth in China, a National Eco-industrial Park Demonstration Program was launched in 2000. This article provides a case study of the Tianjin Economic-Technological Development Area (TEDA). The emergence of an environmental institution in TEDA is used as a backdrop to assess how TEDA has transformed itself into one of the top three national eco-industrial parks in China. Following two years of field research, a network of 81 inter-firm symbiotic relationships formed in TEDA during the past 16 years were identified involving the utility, automobile, electronics, biotechnology, food and beverage, and resource recovery clusters. The article assesses the environmental benefits of the key symbiotic exchanges in TEDA and summarizes some unique characteristics of EIP progress in a developing country. © 2009 Elsevier Ltd. All rights reserved.

Ke H.-W.,Tianjin University | Li X.-Q.,Nankai University
European Physical Journal C | Year: 2011

While the light-front quark model (LFQM) is employed to calculate hadronic transition matrix elements, the vertex functions must be pre-determined. In this work we derive the vertex functions for all d-wave states in this model. Especially, since both 3D1 and 3S1 are 1-- mesons, the Lorentz structures of their vertex functions are the same. Thus when one needs to study the processes where 3D1 is involved, all the corresponding formulas for 3S1 states can be directly applied; only the coefficient of the vertex function should be replaced by that for 3D1. The results would be useful for studying the newly observed resonances, which are supposed to be d-wave mesons, and furthermore possible 2S-1D mixing in ψ′ with the LFQM. © 2011 Springer-Verlag / Società Italiana di Fisica.

Wang C.-C.,Tianjin University | Niu Z.-G.,Tianjin University | Zhang Y.,Nankai University
Journal of Hazardous Materials | Year: 2013

To estimate the concentration in air and the cancer risk of irrigation workers and the public exposed to the total trihalomethanes (TTHMs) in reclaimed water used for landscape irrigation, a probabilistic health risk assessment was conducted through the integrated use of one-dimensional (1-D) and two-dimensional (2-D) Monte Carlo simulations. Before the 2-D simulation, a sensitivity analysis corresponding to the 1-D simulation was carried out to identity the factors most affecting the outputs. The results reveal that the TTHM concentration level and cancer risk for workers' exposure is much higher than that for public exposure in landscape irrigation. Moreover, the most influential factors are quite different for workers' exposure and public exposure. The 2-D Monte Carlo risk analysis result for the workers indicated that the lowest-risk, highest-risk and two critical points for irrigation height are 0.7. m, 1.53. m, 1.4. m and 1.65. m when the mean value of the risk is selected as the reference statistic for risk management. Based on the risk assessment results, different measures can be suggested for the risk control of different populations. Furthermore, the influential variables should be better characterized to improve the accuracy of health risk assessment. © 2013 Elsevier B.V.

Yuan F.-F.,Nankai University | Huang P.,Sun Yat Sen University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

In this note, we use the disformal transformation to induce a geometry from the manifold which is originally Riemannian. The new geometry obtained here can be considered as a generalization of Weyl integrable geometry. Based on these results, we further propose a geometry which is naturally a generalization of Weyl geometry. © 2015 The Authors.

Dong X.-Q.,Wuhan University | Fang X.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Organic Letters | Year: 2011

The first asymmetric sulfa-Michael addition of thiols to 4,4,4-trifluorocrotonates for the construction of a stereogenic center bearing a unique trifluoromethyl group and a sulfur atom has been achieved in high yields and excellent enantioselectivities with a 1 mol % bifunctional organocatalyst. Subsequent transformation led to the expedient preparation of enantioenriched thiochroman-4-one and the key intermediate of the potent inhibitor of MMP-3, (R)-γ-trifluoromethyl γ-sulfone hydroxamate. © 2011 American Chemical Society.

Jin Z.,Nankai University
Natural Product Reports | Year: 2013

Structurally diverse alkaloids containing five-membered heterocyclic subunits, such as imidazole, oxazole, thiazole, as well as their saturated congeners, are widely distributed in terrestrial and marine organisms and microorganisms. These naturally occurring secondary metabolites often exhibit extensive and pharmacologically important biological activities. The latest progress involving isolation, biological activities, chemical synthetic studies, and biosynthetic pathways of these natural products has been summarized in this review. © 2013 The Royal Society of Chemistry.

Gao J.,Nankai University | Kurgan L.,University of Alberta
Methods in Molecular Biology | Year: 2014

Computational identification of B-cell epitopes from antigen chains is a difficult and actively pursued research topic. Efforts towards the development of method for the prediction of linear epitopes span over the last three decades, while only recently several predictors of conformational epitopes were released. We review a comprehensive set of 13 recent approaches that predict linear and 4 methods that predict conformational B-cell epitopes from the antigen sequences. We introduce several databases of B-cell epitopes, since the availability of the corresponding data is at the heart of the development and validation of computational predictors. We also offer practical insights concerning the use and availability of these B-cell epitope predictors, and motivate and discuss feature research in this area. © Springer Science+Business Media New York 2014.

Yang J.,University Paris - Sud | Sauvan C.,University Paris - Sud | Sauvan C.,Institut Universitaire de France | Liu H.T.,Nankai University | And 2 more authors.
Physical Review Letters | Year: 2011

We theoretically study fishnet metamaterials at optical frequencies. In contrast with earlier works, we provide a microscopic description by tracking the transversal and longitudinal flows of energy through the fishnet mesh composed of intersecting subwavelength plasmonic waveguides. The analysis is supported by a semianalytical model based on surface-plasmon coupled-mode equations, which provides accurate formulas for the fishnet refractive index, including the real-negative and imaginary parts. The model simply explains how the surface plasmons couple at the waveguide intersections, and it shines new light on the fishnet negative-index paradigm at optical frequencies. Extension of the theory for loss-compensated metamaterials with gain media is also presented. © 2011 American Physical Society.

Yao Q.,Nankai University | Moskowitz D.S.,McGill University
Journal of Personality | Year: 2015

The present study examined the influence of trait Agreeableness and its interaction with social role status on interpersonal correspondence as reflected in the within-person relation between a person's communal (agreeable-quarrelsome) behavior and perceptions of the interaction partner's communal behavior. We used a sample of working adults (original data set: 113 participants and 12,303 interpersonal events; constrained data set in the work setting: 109 participants and 3,193 interpersonal events) and an event-contingent recording procedure to assess behavior in naturalistic interpersonal events. The results of multilevel modeling indicated that interpersonal correspondence was lower for high trait Agreeableness persons than for low trait Agreeableness persons, apparently due to less responsiveness to more disagreeable behavior by the other person in an interaction. High Agreeableness persons manifest greater interpersonal correspondence when in a high-status role than when in a low-status role, apparently by increasing responsiveness to disagreeable behavior from others. The results imply that high social role status may influence the effortful control process of high trait Agreeableness persons over their behavioral reactions to others' disagreeable behavior during interpersonal interactions. © 2014 Wiley Periodicals, Inc.

Su L.X.,Nankai University
American journal of critical care : an official publication, American Association of Critical-Care Nurses | Year: 2012

Timely diagnosis and prognostic assessment of ventilator-associated pneumonia remain major challenges in critical care. To explore the value of soluble triggering receptor expressed on myeloid cells 1, procalcitonin, and the Clinical Pulmonary Infection Score in the diagnosis and prognostic assessment of ventilator-associated pneumonia. For 92 patients, bronchoalveolar lavage fluid was cultured for detection of microorganisms, serum levels of the receptor and procalcitonin and levels of the receptor in exhaled ventilator condensate were measured, and the Clinical Pulmonary Infection Score was calculated. On the day of diagnosis, patients who had pneumonia had higher serum levels of the receptor, procalcitonin, and C-reactive protein; higher white blood cell counts; and higher pulmonary infection and Sequential Organ Failure Assessment scores than did patients without pneumonia. White blood cell count (odds ratio, 1.118; 95% CI, 1.139-1.204) and serum levels of the receptor (odds ratio, 1.002; 95% CI, 1.000-1.005) may be risk factors for VAP. Serum levels of the receptor plus the pulmonary infection score were the most reliable for diagnosis; the area under the receiver operating characteristic curve was 0.972 (95% CI, 0.945-0.999), sensitivity was 0.875, and specificity was 0.95. For 28-day survival, procalcitonin level combined with pulmonary infection score was the most reliable for prognostic assessment (area under the curve, 0.848; 95% CI, 0.672-1.025). In patients with ventilator-associated pneumonia, serum levels of the receptor plus the pulmonary infection score are useful for diagnosis, and procalcitonin levels plus the pulmonary infection score are useful for prognostic assessment.

Xia Q.,Zhejiang University | Liu X.,Zhejiang University | Zhang Y.,Zhejiang University | Chen C.,Zhejiang University | And 2 more authors.
Organic Letters | Year: 2013

The copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagent are described. Various amides and carboxylic acids were methylated affording N-substituted amides and esters. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process. © 2013 American Chemical Society.

Fang X.,Wuhan University | Li J.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Organic Letters | Year: 2013

A highly efficient organocatalytic asymmetric SMA reaction of hexafluoroisopropyl α,β-unsaturated esters has been developed. Introducing electron-withdrawing hexafluoroisopropyl ester is crucial to enhancing the electrophilicity of unsaturated esters as SMA acceptors. The catalytic system performs well over a broad scope of α,β-unsaturated esters and diversified thiols and provides facile access to (R)-thiazesim in a one-pot protocol. © 2013 American Chemical Society.

Liao Y.,Nankai University | Liao Y.,Peking University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We study higher-dimensional neutrino mass operators in a low energy theory that contains a second Higgs doublet, the two Higgs doublet model. The operators are relevant to underlying theories in which the lowest dimension-five mass operators would not be induced. We list the independent operators with dimension up to nine with the help of Young tableau. Also listed are the lowest dimension-seven operators that involve gauge bosons and violate the lepton number by two units. We briefly mention some of possible phenomenological implications. © 2011 Elsevier B.V.

Zhang F.,Beijing Normal University | Song H.,Nankai University | Zi G.,Beijing Normal University
Dalton Transactions | Year: 2011

A new series of group 5 metal amides have been prepared from the reaction between V(NMe2)4 or M(NMe2)5 (M = Nb, Ta) and chiral ligands, (R)-2,2′-bis(mesitoylamino)-1,1′- binaphthyl (1H2), (R)-5,5′,6,6′,7,7′,8,8′- octahydro-2,2′-bis(mesitoylamino)-1,1′-binaphthyl (2H2), (R)-6,6′-dimethyl-2,2′-bis(mesitoylamino)-1,1′-biphenyl (3H2), (R)-2,2′-bis(mesitylenesulfonylamino)-6,6′- dimethyl-1,1′-biphenyl (4H2), (R)-2,2′- bis(diphenylthiophosphoramino)-1,1′-binaphthyl (5H2), (R)-2,2′-bis[(3-tert-butyl-2-hydroxybenzylidene)amino]-6, 6′-dimethyl-1,1′-biphenyl (6H2), (R)-2,2′-bis[(3,5- di-tert-butyl-2-hydroxybenzylidene)amino]-6,6′-dimethyl-1, 1′-biphenyl (7H2), (R)-2,2′-bis[(3-tert-butyl-2- hydroxybenzylidene)amino]-1,1′-binaphthyl (8H2), (S)-2-(mesitoylamino)-2′-(dimethylamino)-1,1′-binaphthyl (9H), and (R)-2-(mesitoylamino)-2′-(dimethylamino)-6,6′-dimethyl-1, 1′-biphenyl (10H), which are derived from (R) or (S)-2,2′-diamino-1, 1′-binaphthyl, and (R)-2,2′-diamino-6,6′-dimethyl-1,1′- biphenyl, respectively. Treatment of V(NMe2)4 or M(NMe2)5 (M = Nb, Ta) with 1 equiv of C 2-symmetric amidate ligands 1H2, 2H2, 3H 2, 4H2, and 5H2, or Schiff base ligands 6H 2, 7H2 and 8H2 at room temperature gives, after recrystallization from a benzene, toluene or n-hexane solution, the vanadium amides (1)V(NMe2)2 (11), (2)V(NMe2)2 (14), (3)V(NMe2)2 (17), (5)V(NMe2)2 (22), (6)V(NMe2)2 (23) and (7)V(NMe2) 2 (24), and niobium amides (1)Nb(NMe2)3 (12), (2)Nb(NMe2)3 (15), (3)Nb(NMe2)3 (18), (4)Nb(NMe2)3 (20) and [2-(3-Me3C-2-O- C6H3CHN)-2′-(N)-C20H12][2- (Me2N)2CH-6-CMe3-C6H 3O]NbNMe2·C7H8 (25·C7H8), and tantalum amides (1)Ta(NMe 2)3 (13), (2)Ta(NMe2)3 (16), (3)Ta(NMe2)3 (19) and (4)Ta(NMe2)3 (21) respectively, in good yields. Reaction of V(NMe2)4 or M(NMe2)5 (M = Nb, Ta) with 2 equiv of C 1-symmetric amidate ligands 9H or 10H at room temperature gives, after recrystallization from a toluene or n-hexane solution, the chiral bis-ligated vanadium amides (9)2V(NMe2) 2·3C7H8 (27·3C7H 8) and (10)V(NMe2)2 (28), and chiral bis-ligated metallaaziridine complexes (10)2M(NMe2) (η2-CH2NMe) (M = Nb (29), Ta (30)) respectively, in good yields. The niobium and tantalum amidate complexes are stable in a toluene solution at or below 160 °C, while the vanadium amidate complexes degrade via diemthylamino group elimination at this temperature. For example, heating the complex (2)V(NMe2)2 (14) in toluene at 160 °C for four days leads to the isolation of the complex [(2)V]2(μ-NMe 2)2 (26) in 58% yield. These new complexes have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of complexes 12, 13, and 15-30 have further been confirmed by X-ray diffraction analyses. The vanadium amides are active chiral catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in moderate to good yields with good ee values (up to 80%), and the tantalum amides are outstanding chiral catalysts for the hydroaminoalkylation, giving chiral secondary amines in good yields with excellent ee values (up to 93%). © 2011 The Royal Society of Chemistry.

Ji Q.-P.,Nankai University
Nuclear and Particle Physics Proceedings | Year: 2016

Recent progress on the charmonium-like states (or called XYZ states) from BESIII experiment based on large data samples above DD[U+203E] threshold is presented in this talk, including the observation of X(3823) in the process e+e-→π+π-X(3823)→π+π-γχc1, the observation of X(3872) from radiative decay of the Y(4260), the study of the Y states from the e+e-→π+π-hc, ωχc0, ηJ/ψ and η'J/ψ, and the observation of the Zc states. © 2016 Elsevier B.V.

Wang Y.,CAS Beijing National Laboratory for Molecular | Zhang W.-X.,CAS Beijing National Laboratory for Molecular | Zhang W.-X.,Nankai University | Wang Z.,CAS Beijing National Laboratory for Molecular | Xi Z.,CAS Beijing National Laboratory for Molecular
Angewandte Chemie - International Edition | Year: 2011

Concise and selective: The procedure-controlled synthesis of the title compounds has been achieved for the first time by an organolithium-promoted convergent tandem annulation involving readily available terminal alkynes, chalcogen elements (S, Se, and Te), carbodiimides, and acid chlorides. A novel 1,5-acyl migration is considered to be essential for this useful transformation. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu J.,Northeast Normal University | Liu Z.,Northeast Normal University | Wu N.,Northeast Normal University | Liao P.,Northeast Normal University | And 2 more authors.
Chemistry - A European Journal | Year: 2014

Cross-coupling reactions between propargylic alcohols and isocyanides, by means of silver catalysis, have been described. This new reaction is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable 2,3-allenamides in moderate to excellent yields. Making allenamides: Cross-coupling reactions between propargylic alcohols and isocyanides, by means of silver catalysis, are described. This new reaction is both atom and step efficient and is applicable to a broad scope of substrates, allowing the synthesis of a range of synthetically valuable 2,3-allenamides in moderate to excellent yields (see scheme). Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li B.,CAS Beijing National Laboratory for Molecular | Wu Z.-H.,CAS Beijing National Laboratory for Molecular | Gu Y.-F.,CAS Beijing National Laboratory for Molecular | Sun C.-L.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2011

Go go Grignard! The first highly regioselective, cobalt-catalyzed C-H transformation of benzo[h]quinoline and phenylpyridine derivatives with Grignard reagents at room temperature has been achieved (see scheme). Both aryl and alkyl Grignard reagents showed significant reactivity. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ke H.-W.,Tianjin University | Liu T.,Tianjin University | Li X.-Q.,Nankai University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

The LHCb Collaboration has systematically measured the rates of Bc→J/ψK, Bc→J/ψDs, Bc→J/ψDs*, and Bc→ψ(2S)π. The new data enable us to study relevant theoretical models and further determine the model parameters. In this work, we calculate the form factors for the transitions Bc→J/ψ and Bc→ψ(2S) numerically and then determine the partial widths of the semileptonic and nonleptonic decays. The theoretical predictions on the ratios of Γ(Bc→J/ψK)/Γ(Bc→J/ψπ), Γ(Bc→J/ ψDs)/Γ(Bc→J/ψπ), and Γ(Bc→J/ψDs*)/ Γ(Bc→J/ψπ) are consistent with data within only 1σ. Especially, for calculating Γ(Bc→ψ(2S)X) the modified harmonic oscillator wave function which we developed in early works is employed, and the results indicate that the modified harmonic oscillator wave function works well. © 2014 American Physical Society.

Zhou Q.-X.,China University of Petroleum - Beijing | Gao Y.-Y.,Nankai University
Chinese Chemical Letters | Year: 2014

A temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with high performance liquid chromatography was developed for the enrichment and determination of triazine herbicides such as cyanazine, simazine, and atrazine in water samples. 1-Octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) was selected as the extraction solvent. Several experimental parameters were optimized. Under the optimal conditions, the linear range for cyanazine was in the concentration range of 0.5-80 μg/L and the linear range for simazine and atrazine was in the range of 1.0-100 μg/L. The limit of detection (LOD, S/N = 3) was in the ranges of 0.05-0.06 μg/L, and the intra day and inter day precision (RSDs, n = 6) was in the ranges of 3.2%-6.6% and 4.8%-8.9%, respectively. Four real water samples were analyzed with the developed method, and the experimental results showed that the spiked recoveries were satisfactory. All these exhibited that the developed method was a valuable tool for monitoring such pollutants. © 2014 Qing-Xiang Zhou. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Chu J.,CAS Shanghai Institute of Organic Chemistry | Lu E.,CAS Shanghai Institute of Organic Chemistry | Liu Z.,CAS Shanghai Institute of Organic Chemistry | Chen Y.,CAS Shanghai Institute of Organic Chemistry | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

A complex complex: The reactions of a scandium terminal imido complex with a series of unsaturated substrates, including CO2, PhCN, methyl methacrylate (MMA), cyclopentadiene, PhNCO, and propylene oxide, are presented (see scheme). A variety of intriguing products are formed from this complex. Ar=2,6-(iPr)2C6H3. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jin L.,Nankai University
Annals of Physics | Year: 2016

Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov-Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms. © 2016 Elsevier Inc.

Li K.,Nankai University | Du T.C.,Chinese University of Hong Kong
Decision Support Systems | Year: 2012

Over the years, mobile advertising has grown to become a technology that allows an advertiser to promote products or services to targeted users efficiently and effectively. This is because the ubiquitous nature of mobile devices can provide contextual information and allow users to demonstrate preferences. This study proposes a targeted mobile advertising system (TMAS) that works as a platform to provide both merchants and consumers with context-aware advertisements. The approach integrates the advantages of both mobile and targeted advertising to allow merchants to disseminate location-based targeted advertisements while providing pull-type and personalized advertisements for consumers. To demonstrate the TMAS, we build a platform to provide highly relevant advertising to consumers and to guarantee that advertisements have an equal opportunity of being presented to consumers. © 2012 Elsevier B.V. All rights reserved.

Hong P.,Nanjing University of Science and Technology | Zhang G.,Nankai University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Recently, we have demonstrated that second-order subwavelength interference could be realized in an optical lithography scheme with an effective entangled source [P. Hong and G. Zhang, Phys. Rev. A 88, 043838 (2013)PLRAAN1050-294710.1103/PhysRevA.88.043838]. In this paper, by considering the correlation function in both the source plane and observation plane, we show how the coherence property of such a source is controlled via introduction of random-phase correlation, which finally affects the two-photon interference effect observed in the far-field plane. Furthermore, by introducing different but similar random-phase correlations, we generalize the phase controlled source with particular high-order coherence properties to obtain higher-order subwavelength interference, i.e., high-order super-resolved optical lithography. These results show the importance of phase control in generating a light field with particular high-order coherence properties. ©2015 American Physical Society.

Jin Z.,Nankai University
Natural Product Reports | Year: 2013

Recent progress on the isolation, identification, biological activity and synthetic studies of structurally diverse alkaloids from plants of the family Amaryllidaceae is summarized in this review. In addition, the structurally related alkaloids isolated from Sceletium species are discussed as well. © 2013 The Royal Society of Chemistry.

Xie J.,Nanjing University | Huang Z.-Z.,Nanjing University | Huang Z.-Z.,Nankai University
Angewandte Chemie - International Edition | Year: 2010

The direct approach: The title coupling reactions of N-aryl glycine esters with unmodified ketones occurred smoothly in the presence of tert-butyl hydroperoxide (TBHP) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) under mild conditions (see scheme). The oxidant used for C-H activation determined the selectivity of the reactions for a particular type of ketone substrate. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang F.,Tsinghua University | Cai S.,Tsinghua University | Wang Z.,Tsinghua University | Xi C.,Nankai University
Organic Letters | Year: 2011

An efficient strategy for the synthesis of a variety of 2-mercaptobenzothiazole derivatives has been developed. The reaction proceeded from o-haloaniline derivatives and carbon disulfide via a tandem reaction in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to afford the corresponding 2-mercaptobenzothiazole derivatives in good to excellent yields. © 2011 American Chemical Society.

Hu Y.,Tianjin Medical University | Xu K.,Nankai University | Yague E.,Imperial College London
Breast Cancer Research and Treatment | Year: 2015

Multidrug resistance (MDR) remains one of the most significant obstacles in breast cancer treatment, and this process often involves dysregulation of a great number of microRNAs (miRNAs). Some miRNAs are indicators of drug resistance and confer resistance to chemotherapeutic drugs, although our understanding of this complex process is still incomplete. We have used a combination of miRNA profiling and real-time PCR in two drug-resistant derivatives of MCF-7 and Cal51 cells. Experimental modulation of miR expression has been obtained by retroviral transfection. Taxol and doxorubicin IC50 values were obtained by short-term drug sensitivity assays. Apoptosis was determined by flow cytometry after annexin V staining, by caspase 3/7 and caspase 9 activity assays and the levels of apoptosis-related proteins bcl-2 and bax by real-time PCR and Western blot. miR target was studied using transient transfection of luciferase constructs with the 3′ untranslated regions (UTR) of target mRNAs. Small interfering RNA-mediated genetic knock-down was performed in MDR cells and its modulatory effect on apoptosis examined. The effect of miRNA on tumorigenicity and tumor drug response was studied in mouse xenografts. miRNA profiling of two drug-resistant breast cancer cell models indicated that miR-218 was down-regulated in both MCF-7/A02 and CALDOX cells. Ectopic expression of miR-218 resensitized both drug-resistant cell lines to doxorubicin and taxol due to an increase in apoptosis. miR-218 binds survivin (BIRC5) mRNA 3′-UTR and down-regulated reporter luciferase activity. Experimental down-regulation of survivin by RNA interference in drug-resistant cells did mimic the sensitization observed when miRNA-218 was up-regulated. In addition, resensitization to taxol was also observed in mouse tumor xenografts from cells over-expressing miR-218. miR-218 is involved in the development of MDR in breast cancer cells via targeting survivin and leading to evasion of apoptosis. Targeting miR-218 and survivin may thus provide a potential strategy for reversing drug resistance in breast cancer. © 2015, Springer Science+Business Media New York.

Wang Y.,CAS Beijing National Laboratory for Molecular | Chi Y.,CAS Beijing National Laboratory for Molecular | Zhang W.-X.,CAS Beijing National Laboratory for Molecular | Zhang W.-X.,Nankai University | Xi Z.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2012

A highly regioselective base-mediated ring expansion of 2,4-diiminoazetidines via cleavage of C-N and C(sp 3)-H bonds is achieved for the first time to afford efficiently 2,3- dihydropyrimidinesulfonamides. The mechanism of the ring expansion via tandem 4π electrocyclic ring-opening/1,5-H shift/6π electrocyclic ring-closing is well confirmed by the trapping experiments of two key intermediates and deuterium labeling studies. © 2012 American Chemical Society.

Chen K.,University of Alberta | Mizianty M.J.,University of Alberta | Gao J.,Nankai University | Kurgan L.,University of Alberta
Structure | Year: 2011

Protein function annotation and rational drug discovery rely on the knowledge of binding sites for small organic compounds, and yet the quality of existing binding site predictors was never systematically evaluated. We assess predictions of ten representative geometry-, energy-, threading-, and consensus-based methods on a new benchmark data set that considers apo and holo protein structures with multiple binding sites for biologically relevant ligands. Statistical tests show that threading-based Findsite outperforms other predictors when its templates have high similarity with the input protein. However, Findsite is equivalent or inferior to some geometry-, energy-, and consensus-based methods when the similarity is lower. We demonstrate that geometry-, energy-, and consensus-based predictors benefit from the usage of holo structures and that the top four methods, Findsite, Q-SiteFinder, ConCavity, and MetaPocket, perform better for larger binding sites. Predictions from these four methods are complementary, and our simple meta-predictor improves over the best single predictor. © 2011 Elsevier Ltd All rights reserved.

Zhao J.,Tianjin Polytechnic University | Wei J.,PLA Military Transportation University | Li Y.,Nankai University
International Journal of Production Economics | Year: 2014

Pricing decisions for two substitutable products in a supply chain with one common retailer and two competitive manufacturers are considered in this paper. The purpose of this paper is to analyze the effects of the two manufacturers different competitive strategies and the channel members different power structures on the optimal pricing decisions. One centralized pricing model and seven decentralized pricing models are developed, and the corresponding analytical equilibrium solutions are obtained by using game-theoretic approach. Finally, numerical studies are presented to illustrate the effectiveness of the theoretical results, and to gain additional managerial insights. © 2014 Elsevier B.V. All rights reserved.

Xu X.,Nankai University | Xu X.,University of California at Los Angeles | Liu P.,University of California at Los Angeles | Shu X.-Z.,University of Wisconsin - Madison | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

The mechanism of Rh-catalyzed (5+2) cycloadditions of 3-acyloxy-1,4-enyne (ACE) and alkynes is investigated using density functional theory calculations. The catalytic cycle involves 1,2-acyloxy migration, alkyne insertion, and reductive elimination to form the cycloheptatriene product. In contrast to the (5+2) cycloadditions with vinylcyclopropanes (VCPs), in which alkyne inserts into a rhodium-allyl bond, alkyne insertion into a Rh-C(sp2) bond is preferred. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity. In the regioselectivity-determining alkyne insertion step, the alkyne substituent prefers to be distal to the forming C-C bond and thus distal to the OAc group in the product. © 2013 American Chemical Society.

Gao G.,Nankai University | Falconer R.A.,University of Cardiff | Lin B.,University of Cardiff | Lin B.,Tsinghua University
Water Research | Year: 2011

Faecal bacteria exist in both free-living and attached forms in surface waters. The deposition of sediments can take faecal bacteria out of the water column and to the bed. The sediments can subsequently be re-suspended into the water column, which can then lead to the re-suspension of the faecal bacteria of the attached form back into the water column, where it may desorb from the sediments. Therefore, the fate and transport of faecal bacteria is highly related to the governing sediment transport processes, particularly where these processes are significant. However, little attempt has been made to model such processes in terms of predicting the impact of the sediment fluxes on faecal bacteria levels. Details are given of the refinement of a numerical model of faecal bacteria transport, where the sediment transport processes are significant. This model is based on the model DIVAST (Depth Integrated Velocities And Solute Transport). Analytical solutions for steady and uniform flow conditions were derived and used to test the sediment-bacteria interaction model. After testing the sediment-bacteria interaction model favourably against known results, the model was then set up for idealised case studies to investigate the effects of sediment on bacteria concentrations in the water column. Finally the model was applied to a simplified artificial flooding study to investigate the impact of suspended sediment fluxes on the corresponding bacteria transport processes. The model predictions have proved to be encouraging, with the results being compared to field measurements. © 2011 Elsevier Ltd.

Lin G.-J.,Xiamen University | Zheng X.,Xiamen University | Huang P.-Q.,Xiamen University | Huang P.-Q.,Nankai University
Chemical Communications | Year: 2011

An efficient and highly diastereoselective method for the construction of the hydroxylated tropane skeleton is described. The method features a new intramolecular reductive coupling reaction of N-acyl N,O-acetal with aldehyde, cooperatively mediated by BF 3·OEt 2 and SmI 2. On the basis of this method, a new enantioselective total synthesis of (-)-Bao Gong Teng A has been accomplished. © 2011 The Royal Society of Chemistry.

This study focused on the effects of zinc oxide nanoparticles (nano-ZnO) on spatial learning and memory and synaptic plasticity in the hippocampus of young rats, and tried to interpret the underlying mechanism. Rats were randomly divided into four groups. Nano-ZnO and phosphate-buffered saline were administered in 4-week-old rats for 8 weeks. Subsequently, performance in Morris water maze (MWM) was determined, and then long-term potentiation (LTP) and depotentiation were measured in the perforant pathway to dentate gyrus (DG) in anesthetized rats. The data showed that, (1) in MWM, the escape latency was prolonged in the nano-ZnO group and, (2) LTP was significantly enhanced in the nano-ZnO group, while depotentiation was barely influenced in the DG region of the nano-ZnO group. This bidirectional effect on long-term synaptic plasticity broke the balance between stability and flexibility of cognition. The spatial learning and memory ability was attenuated by the alteration of synaptic plasticity in nano-ZnO-treated rats.

Xin W.,Chinese PLA General Hospital | Wei W.,Nankai University | Li X.,Chinese PLA General Hospital
Heart | Year: 2012

Context The effects of fish oil on cardiac function, ventricular remodelling and functional capacity in patients with chronic heart failure (CHF) remain controversial. Objective The aim of this meta-analysis was to evaluate effects of fish oil on cardiac function and related parameters in CHF patients. Data Sources Medline, Embase, the Cochrane Library and references cited in related reviews and studies. Study Selection Randomised controlled trials of fish oil supplementation on cardiac function in patients with CHF were identified. Data Extraction Two investigators read all papers and extracted all relevant information. A fixed effect or, in the presence of heterogeneity, a random effect model, was used to estimate the combined effects. Results 7 trials with 825 participants were included. Meta-analysis results showed that left ventricular ejection fraction was significantly increased (weighted mean difference (WMD) = 2.25%, 95% CI 0.66 to 3.83, p = 0.005) and left ventricular end-systolic volume was significantly decreased (WMD = 7.85 ml, 95% CI -15.57 to -0.12, p = 0.05) in the fish oil group compared with the placebo group, although left ventricular end-diastolic volume was not significantly affected. Meta-regression and subgroup analysis indicated that the improvement in left ventricular systolic function was more remarkable in patients with nonischaemic heart failure. Fish oil supplementation also improved the New York Heart Association functional classification and peak oxygen consumption in patients with non-ischaemic heart failure. Conclusions Improvement in cardiac function, remodelling and functional capacity may be important mechanisms underlying the potential therapeutic role of fish oil for patients with CHF. These effects might be more remarkable in patients with non-ischaemic heart failure. INTRODUCTION Chronic heart failure (CHF) is a complex clinical syndrome characterised by insufficient status of cardiac function, which can be caused by various structural or functional cardiovascular disorders.1 Despite impressive advances in medical management and device therapy in recent decades, CHF remains one of the leading causes of cardiovascular morbidity and mortality worldwide.2 3 Thus there is an urgent need for the development of novel treatment strategies for CHF despite the standard pharmacological therapies that have been recommended by current medical guidelines.4 5 Numerous clinical trials have shown supplementation with fish oil, which mainly consists of two categories of marine omega 3 polyunsaturated fatty acidsdeicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)dmay lower the risk of major cardiovascular events, such as myocardial infarction, sudden cardiac death (SCD), coronary artery disease and perhaps atrial fibrillation.6 7 Growing evidence from experimental and epidemiological studies suggested that fish oil intake could be beneficial for patients with CHF.8 9 Previous studies also indicated that fish oil could improve cardiac function and functional capacity in CHF patients; however, clinical trials have shown inconsistent results.10-16 Therefore, we performed a metaanalysis to systematically evaluate the effects of fish oil on cardiac function, remodelling and functional capacity in CHF. METHODS The study complied with the recently reported Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

Dehmer M.,Institute for Bioinformatics and Translational Research | Shi Y.,Nankai University
PLoS ONE | Year: 2014

In this paper, we examine the uniqueness (discrimination power) of a newly proposed graph invariant based on the matrix DMAX defined by Randić et al. In order to do so, we use exhaustively generated graphs instead of special graph classes such as trees only. Using these graph classes allow us to generalize the findings towards complex networks as they usually do not possess any structural constraints. We obtain that the uniqueness of this newly proposed graph invariant is approximately as low as the uniqueness of the Balaban J index on exhaustively generated (general) graphs. Copyright: © 2014 Dehmer, Shi.

Liu B.,Zhejiang University | Zhou Y.,Zhejiang University | Chen W.,Zhejiang University | Chen W.,Nankai University
Organometallics | Year: 2010

Reactions of the imidazolium salts or their corresponding silver carbene complexes with copper powder afforded unusual copper(II) hydroxide complexes of N-heterocyclic carbenes: [Cu2(μ-OH)(L1)](PF6) 2 (2; L1 = 3,5-bis(N-picolylimidazolylidenylmethy1)pyrazolate), [Cu4(μ3-OH)2(L2)2](PF 6)4 (3; L2 = 3,5-bis(N-pyridylimidazolylidenylmethy1) pyrazolate), and [Cu4(μ3-OH)2(L3) 2](PF6)4 (4; L3 = 3,5-bis(N- pyrimidylimidazolylidenylmethy1)pyrazolate). The same reaction of 3,5-bis(N-thiophenylimidazoliumylmethy1)pyrazole yielded a dinuclear Cu(II)-NHC complex, [Cu2(L4)2] (PF6)2 (5; L4 = 3,5-bis(N-thiophenylimidazolylidenylmethy1)pyrazolate). The complexes have been fully characterized by X-ray diffraction analysis, elemental analysis, and IR and ESI-MS spectra. A catalytic study shows that complex 4 is highly active in the N-arylation reactions of imidazoles and aromatic amines with arylboronic acids in methanol at room temperature under base-free conditions. © 2010 American Chemical Society.

Wu B.,Harvard University | Peisley A.,Harvard University | Richards C.,Program in Cellular and Molecular Medicine | Yao H.,Nankai University | And 6 more authors.
Cell | Year: 2013

MDA5, a viral double-stranded RNA (dsRNA) receptor, shares sequence similarity and signaling pathways with RIG-I yet plays essential functions in antiviral immunity through distinct specificity for viral RNA. Revealing the molecular basis for the functional divergence, we report here the crystal structure of MDA5 bound to dsRNA, which shows how, using the same domain architecture, MDA5 recognizes the internal duplex structure, whereas RIG-I recognizes the terminus of dsRNA. We further show that MDA5 uses direct protein-protein contacts to stack along dsRNA in a head-to-tail arrangement, and that the signaling domain (tandem CARD), which decorates the outside of the core MDA5 filament, also has an intrinsic propensity to oligomerize into an elongated structure that activates the signaling adaptor, MAVS. These data support a model in which MDA5 uses long dsRNA as a signaling platform to cooperatively assemble the core filament, which in turn promotes stochastic assembly of the tandem CARD oligomers for signaling. © 2013 Elsevier Inc.

Zhang T.,Nankai University
Sheng li xue bao : [Acta physiologica Sinica] | Year: 2011

As a rhythmic neural activity, neural oscillation exists all over the nervous system, in structures as diverse as the cerebral cortex, hippocampus, subcortical nuclei and sense organs. This review firstly presents some evidence that synchronous neural oscillations in theta and gamma bands reveal much about the origin and nature of cognitive processes such as learning and memory. And then it introduces the novel analyzing algorithms of neural oscillations, which is a directionality index of neural information flow (NIF) as a measure of synaptic plasticity. An example of application used such an analyzing algorithms of neural oscillations has been provided.

Zhu L.-N.,Tianjin University | Wu B.,Tianjin University | Kong D.-M.,Tianjin University | Kong D.-M.,Nankai University
Nucleic Acids Research | Year: 2013

Ligands targeting telomeric G-quadruplexs are considered good candidates for anticancer drugs. However, current studies on G-quadruplex ligands focus exclusively on the interactions of ligands and monomeric G-quadruplexes under dilute conditions. Living cells are crowded with biomacromolecules, and the ∼200-nucleotide G-rich single-stranded overhang of human telomeric DNA has the potential to fold into multimeric G-quadruplex structures containing several G-quadruplex units. Studies on interactions between ligands and multimeric G-quadruplexes under molecular crowding conditions could provide a new route for screening specific telomeric G-quadruplex-targeting ligands. Herein, TMPipEOPP, a cationic porphyrin derivative designed by us, was demonstrated as a promising multimeric telomeric G-quadruplex ligand under molecular crowding conditions. It could highly specifically recognize G-quadruplexes. It could also promote the formation of G-quadruplexes and stabilize them. Detailed studies showed that TMPipEOPP interacted with monomeric G-quadruplexes in sandwich-like end-stacking mode of quadruplex/TMPipEOPP/quadruplex and interacted with multimeric human telomeric G-quadruplexes by intercalating into the pocket between two adjacent G-quadruplex units. The pocket size greatly affected TMPipEOPP binding. A larger pocket was advantageous for the intercalation of TMPipEOPP. This work provides new insights into the ligand-binding properties of multimeric G-quadruplexes under molecular crowding conditions and introduces a new route for screening anticancer drugs targeting telomeric G-quadruplexes. © 2013 The Author(s).

Chen X.,Nankai University
Soft Computing | Year: 2015

A finite variation process is an uncertain process whose total variation is finite over each bounded time interval. Based on the finite variation processes, a new uncertain integral is proposed in this paper. Besides, some basic properties are discussed. In the framework of the uncertain integral, uncertain differential is introduced, and the fundamental theorem of uncertain calculus is derived. Finally, the integration by parts theorem is studied. © 2014, Springer-Verlag Berlin Heidelberg.

Zhang P.B.,Nankai University
Electronic Journal of Combinatorics | Year: 2015

Bóna conjectured that the descent polynomials on (n − 2)-stack sortable permutations have only real zeros. Brändén proved this conjecture by establishing a more general result. In this paper, we give another proof of Brändén’s result by using the theory of s-Eulerian polynomials recently developed by Savage and Visontai. © 2015, Australian National University. All rights reserved.

Zhang L.,Tianjin University of Technology | Yin Y.,Nankai University
Sensors and Actuators, B: Chemical | Year: 2013

In this paper, flower-like zinc oxide (ZnO) nanorods were successfully synthesized via a simple, cost-effective and environment-friendly wet-chemical method at a relatively low temperature (90 C). X-ray diffraction indicated that the ZnO nanorods are crystallized in a hexagonal wurtzite structure. Electron microscopy observations confirmed the nanorod assembled flower-like morphology. And, high-resolution transmission electron microscopy (HRTEM) images proved that plenty of defects exist on the surface of ZnO nanorods. Photoluminescence analysis showed that abundant intrinsic defects are present on the ZnO crystal surfaces, the content of which is far more than that of commercial ZnO powders. X-ray photoelectron spectrometry revealed that considerable oxygen species (23.29%) chemisorbs on the surface of the as-prepared ZnO nanorods. Gas sensors based on these ZnO nanorods exhibit high response, fast response-recovery and good selectivity to 1-1000 ppm ethanol vapor at 400 C. The excellent ethanol-sensing performance, particularly high response values, is considered to be mainly originated from plenteous defects formed on ZnO surfaces. © 2013 Elsevier B.V. All rights reserved.

Li L.-B.,Nankai University | Hu J.-L.,National Chiao Tung University
Energy Policy | Year: 2012

Most existing energy efficiency indices are computed without taking into account undesirable outputs such as CO 2 and SO 2 emissions. This paper computes the ecological total-factor energy efficiency (ETFEE) of 30 regions in China for the period 2005-2009 through the slack-based model (SBM) with undesirable outputs. We calculate the ETFEE index by comparing the target energy input obtained from SBM with undesirable outputs to the actual energy input. Findings show that China's regional ETFEE still remains a low level of around 0.600 and regional energy efficiency is overestimated by more than 0.100 when not looking at environmental impacts. China's regional energy efficiency is extremely unbalanced: the east area ranks first with the highest ETFEE of above 0.700, the northeast and central areas follow, and the west area has the lowest ETFEE of less than 0.500. A monotone increasing relation exists between the area's ETFEE and China's per capita GDP. The truncated regression model shows that the ratio of R&D expenditure to GDP and the degree of foreign dependence have positive impacts, whereas the ratio of the secondary industry to GDP and the ratio of government subsidies for industrial pollution treatment to GDP have negative effects, on the ETFEE. © 2012 Elsevier Ltd.

Zhang L.,Tianjin University of Technology | Yin Y.,Nankai University
Sensors and Actuators, B: Chemical | Year: 2013

In this contribution, hierarchical tin dioxide (SnO2) nanosheets were successfully synthesized via a simple, cost-effective and environment-friendly hydrothermal method at a relatively low temperature (90 C) after calcination in air. The post-heat treatment not only improved the crystallinity, but also increased the visible emission (refer to intrinsic crystal defects) of the hydrothermal products, which were proved by X-ray diffraction and room temperature photoluminescence, respectively. Electronmicroscopy analysis and nitrogen adsorption-desorption results confirmed the mesoporous feature of these nanosheets. Gas sensors based on these SnO 2 nanosheets exhibited high response, fast response-recovery and good selectivity to 1-1000 ppm ethanol vapor at a relatively low operating temperature (165 C). The excellent ethanol-sensing property, especially high response value can be mainly attributed to the mesoporous texture, characteristically small grain size, abundant surface defects, and the plane-contact feature between the neighboring SnO2 nanosheets. © 2013 Elsevier B.V.

Shen H.,Nankai University | Toki H.,Osaka University | Oyamatsu K.,Aichi Shukutoku University | Sumiyoshi K.,High Energy Accelerator Research Organization
Astrophysical Journal, Supplement Series | Year: 2011

We construct the equation of state (EOS) of dense matter covering a wide range of temperature, proton fraction, and density for the use of core-collapse supernova simulations. The study is based on the relativistic mean-field (RMF) theory, which can provide an excellent description of nuclear matter and finite nuclei. The Thomas-Fermi approximation in combination with assumed nucleon distribution functions and a free energy minimization is adopted to describe the non-uniform matter, which is composed of a lattice of heavy nuclei. We treat the uniform matter and non-uniform matter consistently using the same RMF theory. We present two sets of EOS tables, namely EOS2 and EOS3. EOS2 is an update of our earlier work published in 1998 (EOS1), where only the nucleon degree of freedom is taken into account. EOS3 includes additional contributions from Λ hyperons. The effect of Λ hyperons on the EOS is negligible in the low-temperature and low-density region, whereas it tends to soften the EOS at high density. In comparison with EOS1, EOS2 and EOS3 have an improved design of ranges and grids, which covers the temperature range T = 0.1-10 2.6MeV with the logarithmic grid spacing Δlog 10(T/[MeV]) = 0.04 (92points including T = 0), the proton fraction range Yp = 0-0.65 with the linear grid spacing ΔYp = 0.01 (66points), and the density range ρB = 10 5.1-1016 g cm-3 with the logarithmic grid spacing Δlog10(ρB/[g cm-3]) = 0.1 (110points). © 2011. The American Astronomical Society. All rights reserved.

Li P.,The Key Laboratory of Molecular Microbiology and Technology | Wang L.,Nankai University | Feng L.,Tianjin Key Laboratory of Microbial Functional Genomics
Journal of Bacteriology | Year: 2013

The cold-tolerant bacterium Pusillimonas sp. strain T7-7 is able to utilize diesel oils (C5 to C30 alkanes) as a sole carbon and energy source. In the present study, bioinformatics, proteomics, and real-time reverse transcriptase PCR approaches were used to identify the alkane hydroxylation system present in this bacterium. This system is composed of a Rieske-type monooxygenase, a ferredoxin, and an NADH-dependent reductase. The function of the monooxygenase, which consists of one large (46.711 kDa) and one small (15.355 kDa) subunit, was further studied using in vitro biochemical analysis and in vivo heterologous functional complementation tests. The purified large subunit of the monooxygenase was able to oxidize alkanes ranging from pentane (C5) to tetracosane (C24) using NADH as a cofactor, with greatest activity on the C15 substrate. The large subunit also showed activity on several alkane derivatives, including nitromethane and methane sulfonic acid, but it did not act on any aromatic hydrocarbons. The optimal reaction condition of the large subunit is pH 7.5 at 30°C. Fe2+ can enhance the activity of the enzyme evidently. This is the first time that an alkane monooxygenase system belonging to the Rieske non-heme iron oxygenase family has been identified in a bacterium. © 2013, American Society for Microbiology.

Ren L.,Peking University | Jiao N.,Peking University | Jiao N.,Nankai University
Chemical Communications | Year: 2014

A simple and readily available PdCl2 catalyzed carbamate synthesis method via isocyanate generation and application in situ has been developed. This chemistry provides an efficient and practical approach to synthesize carbamates from simple organic azides, CO atmosphere and alcohols. The broad scope, mild and neutral conditions, and only N2 as the byproduct make this transformation very useful. Moreover, simple examples of modification of bioactive molecules and construction of macrocycles were achieved through this protocol. This journal is © the Partner Organisations 2014.

Zhang J.,Zhengzhou University | Wang K.,Zhengzhou University | Xu Q.,Zhengzhou University | Zhou Y.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
ACS Nano | Year: 2015

To well address the problems of large volume change and dissolution of Fe3O4 nanomaterials during Li+ intercalation/extraction, herein we demonstrate a one-step in situ nanospace-confined pyrolysis strategy for robust yolk-shell nanospindles with very sufficient internal void space (VSIVS) for high-rate and long-term lithium ion batteries (LIBs), in which an Fe3O4@Fe3C core@shell nanoparticle is well confined in the compartment of a hollow carbon nanospindle. This particular structure can not only introduce VSIVS to accommodate volume change of Fe3O4 but also afford a dual shell of Fe3C and carbon to restrict Fe3O4 dissolution, thus providing dual roles for greatly improving the capacity retention. As a consequence, Fe3O4@Fe3C-C yolk-shell nanospindles deliver a high reversible capacity of 1128.3 mAh g-1 at even 500 mA g-1, excellent high rate capacity (604.8 mAh g-1 at 2000 mA g-1), and prolonged cycling life (maintaining 1120.2 mAh g-1 at 500 mA g-1 for 100 cycles) for LIBs, which are much better than those of Fe3O4@C core@shell nanospindles and Fe3O4 nanoparticles. The present Fe3O4@Fe3C-C yolk-shell nanospindles are the most efficient Fe3O4-based anode materials ever reported for LIBs. © 2015 American Chemical Society.

Fu Y.,Harvard University | Fu Y.,Nankai University | Waldor M.K.,Harvard University | Waldor M.K.,Howard Hughes Medical Institute | Mekalanos J.J.,Harvard University
Cell Host and Microbe | Year: 2013

Analysis of genes required for host infection will provide clues to the drivers of evolutionary fitness of pathogens like Vibrio cholerae, a mounting threat to global heath. We used transposon insertion site sequencing (Tn-seq) to comprehensively assess the contribution of nearly all V. cholerae genes toward growth in the infant rabbit intestine. Four hundred genes were identified as critical to V. cholerae in vivo fitness. These included most known colonization factors and several new genes affecting the bacterium's metabolic properties, resistance to bile, and ability to synthesize cyclic AMP-GMP. Notably, a mutant carrying an insertion in tsiV3, encoding immunity to a bacteriocidal type VI secretion system (T6SS) effector VgrG3, exhibited a colonization defect. The reduced in vivo fitness of tsiV3 mutants depends on their cocolonization with bacterial cells carrying an intact T6SS locus and VgrG3 gene, suggesting that the V. cholerae T6SS is functional and mediates antagonistic interbacterial interactions during infection. © 2013 Elsevier Inc.

Gao G.,Harvard University | Gao G.,Nankai University | Vecitis C.D.,Harvard University
ACS Applied Materials and Interfaces | Year: 2012

Electrochemical filtration with anodic carbon nanotube (CNT) networks is reported to be effective for chemical and microbiological water treatment. Here, we investigate how CNT doping affects the electrochemical filtration performance toward the remediation of aromatic wastewaters. Purified and well-characterized undoped (C-CNT), boron-doped (B-CNT), and nitrogen-doped (N-CNT) anodic carbon nanotube networks are challenged with aqueous phenol in a sodium sulfate electrolyte. Steady-state current and effluent total organic carbon (TOC) measurements are utilized to evaluate the oxidative performance as a function of voltage and electrolysis time. In terms of steady-state TOC removal, at an applied voltage of 3 V all three anodic CNT networks are able to remove approximately 7 to 8 mgC L -1 of the influent TOC within the ∼1 s liquid residence time of the electrochemical filter. The anodic CNT networks are partially passivated over the 5 h electrolysis time with the B-CNT network displaying the least passivation. The extent of passivation was observed to be inversely correlated to the CNT work function. SEM, XPS, and TGA of the electrolyzed CNT networks are used to identify the two primary passivation mechanisms of electrochemical phenols polymerization and electrochemical electrolyte precipitation. In agreement with chronoamperometry results, the B-CNT network has the lowest extent of passivating polymer and precipitate formation. The precipitant is determined to likely be sodium persulfate or carbonate and is removed with a simple acidic water wash. The polymer is determined to likely be polyphenylene oxide and is partially removed with the wash. All three anodic CNT networks display potential for energy efficient electrochemical filtration of aromatic wastewaters and the B-CNT are determined to be the most resistant to passivation. © 2012 American Chemical Society.

Xue Z.-Y.,Wuhan University | Li Q.-H.,Wuhan University | Tao H.-Y.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Journal of the American Chemical Society | Year: 2011

A novel catalytic asymmetric Michael addition of azomethine ylide with β-substituted alkylidene bisphosphates was realized in the presence of a chiral copper(I)/TF-BiphamPhos complex. The present system provides a unique and facile access to enantioenriched unnatural α-amino acid derivatives containing gem-bisphosphonates (gem-BPs) in high yields with excellent diastereoselectivities and enantioselectivities. Subsequent transformations lead to the expedient preparation of biologically active unnatural α-amino acid derivatives containing BPs and bisphosphonic acids without loss of diastereo- and enantiomeric excess. © 2011 American Chemical Society.

Jin Z.,Nankai University
Natural Product Reports | Year: 2011

A great number of structurally diverse natural products containing five-membered heterocyclic subunits, such as imidazole, oxazole, thiazole, and their saturated congeners, are abundant in nature. These naturally occurring metabolites often exhibit extensive and pharmacologically important biological activities. The latest progress in the isolation, biological activities, chemical synthetic studies, and biosynthetic pathways on these natural products is summarized in this review. © 2011 The Royal Society of Chemistry.

Zhao J.,University of Science and Technology Beijing | Yang Q.,Nankai University
Inverse Problems | Year: 2011

The multiple-sets split feasibility problem (MSFP) is to find a point closest to the intersection of a family of closed convex sets in one space, such that its image under a linear transformationwill be closest to the intersection of another family of closed convex sets in the image space. This problem arises in many practical fields, and it can be a model for many inverse problems. Noting that some existing algorithms require estimating the Lipschitz constant or calculating the largest eigenvalue of the matrix, in this paper, we first introduce a self-adaptive projectionmethod by adoptingArmijo-like searches to solve the MSFP, then we focus on a special case of the MSFP and propose a relaxed self-adaptivemethod by using projections onto half-spaces instead of those onto the original convex sets, which is much more practical. Convergence results for both methods are analyzed. Preliminary numerical results show that our methods are practical and promising for solving larger scale MSFPs. © 2011 IOP Publishing Ltd.

Liu H.,Nankai University | Lalanne P.,ParisTech Optics Institute
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We present a simple and intuitive model for analyzing the optical response of metallic surfaces patterned by arbitrary one-dimensional arrays of subwavelength (sub- λ) structures. In the present microscopic approach, the near-field response close to the surface is composed of a linear combination of elementary hybrid waves, which are shown to solely depend on the frequency and to be merely independent of the incident illumination and of the scatterer geometry. The model is tested against fully vectorial computational results obtained for simple systems that can be handled numerically with fully vectorial methods and, in contrast to classical models that solely rely on surface plasmon polaritons, the present model is shown to be highly accurate over a broad spectral range below the plasma frequency of the metal. © 2010 The American Physical Society.

Yu J.-S.,East China Normal University | Liu Y.-L.,East China Normal University | Tang J.,East China Normal University | Wang X.,University of Sichuan | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

A remarkable fluorine effect on "on water" reactions is reported. The C-FaH-O interactions between suitably fluorinated nucleophiles and the hydrogen-bond network at the phase boundary of oil droplets enable the formation of a unique microstructure to facilitate on water catalyst-free reactions, which are difficult to realize using nonfluorinated substrates. Accordingly, a highly efficient on water, catalyst-free reaction of difluoroenoxysilanes with aldehydes, activated ketones, and isatylidene malononitriles was developed, thus leading to the highly efficient synthesis of a variety of α,α- difluoro-β-hydroxy ketones and quaternary oxindoles. It's on! The C-FaH-O interactions between suitably fluorinated nucleophiles and a hydrogen-bond network at the phase boundary of an oil droplet facilitate "on water" catalyst-free reactions. Accordingly, the title reaction of difluoroenoxysilanes with aldehydes, activated ketones, and isatylidene malononitriles was developed, thus leading to α,α-difluoro-β-hydroxy ketones and quaternary oxindoles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Let G be a simple graph with n vertices and let λ 1, λ 2, . . . , λ n be the eigenvalues of its adjacency matrix. The Estrada index EE of G is the sum of the terms e λi. Let τ(p, q) denote the set of all trees with a given (p, q)-bipartition, where q ≥ p ≥ 2. And D(p, q) denotes the double star which is obtained by joining the centers of two stars S p and S q by an edge. In this note, we will show that D(p, q) has the maximal Estrada index in τ(p, q).

Liu M.,Nankai University | La Croix S.,University of Hawaii at Manoa
Research Policy | Year: 2015

Building on the seminal work of Ginarte and Park (1997. Research Policy. 26, 283-301), we develop an index of property rights in pharmaceutical inventions, the Pharmaceutical Intellectual Property Protection (PIPP) Index, for 154 countries spanning 1960 to 2005. It incorporates five types of property rights in pharmaceuticals; six statutory measures of enforcement; and adherence to three international agreements providing for the grant and enforcement of rights to foreigners. For both developed and developed countries, the PIPP Index starts at low levels in 1960, increases slowly through the early 1990s, and then sharply increases due to minimum standards set by the 1995 TRIPS Agreement. © 2014 Elsevier B.V. All rights reserved.

Tong M.-C.,Wuhan University | Chen X.,Wuhan University | Li J.,Wuhan University | Huang R.,Wuhan University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2014

An unprecedented catalytic asymmetric inverse-electron-demand aza-Diels-Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]-fused indoline heterocycles were achieved in generally good yields (up to 97 %) with high regioselectivity and diastereoselectivity (>20:1 d.r.), and with excellent enantioselectivity (up to 99 % ee). In(verse) demand: The unprecedented catalytic asymmetric inverse-electron-demand aza-Diels-Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]-fused indoline heterocycles were produced in generally good yields with high regioselectivity and diastereoselectivity, and with excellent enantioselectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kong X.,Nankai University
Journal of the American Society for Mass Spectrometry | Year: 2014

To better understand inconsistencies between the predicted infrared (IR) spectra of previously suggested isomers of Lys2H+ reported by Wu et al. (J. Am. Soc. Mass Spectrom. 22:1651-1659, 18) and the experimental IR photon dissociation (IRPD) spectrum obtained by Oh et al. (J. Am. Chem. Soc. 127:4076-4083, 4), the structure of Lys2H+ was reinvestigated using IRPD spectroscopy in the extended region 2700-3700 cm -1 and theoretical calculations. The new experimental IRPD spectrum is in good agreement with Oh's spectrum in the corresponding wavelength range. Based on calculations at the MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p) and MP2/6-31 + G(d,p)//MP2/6-31 + G(d,p) levels, a new salt-bridged isomer, ZW1, was found to be the most stable isomer; it is more energetically favored than the previously suggested charge-solvated isomer LL-CS01 by 10 or 26 kJ mol -1. Although the calculated IR spectrum of ZW1 is in good agreement with the experimental one in the range 2700-3700 cm-1, it is in poor agreement with the previous IRPD spectrum in the range 1000-1900 cm -1. This investigation shows that the intermolecular interactions inside the dimer are more complex than previously supposed. It is possible that both salt-bridged and charge-solvated isomers of Lys2H+ are stable in the gas phase, and the isomers generated during ionization are sensitive to the experimental conditions. [Figure not available: see fulltext.] © 2014 American Society for Mass Spectrometry.

Fang Z.,Northeast Normal University | Liu J.,Northeast Normal University | Liu Q.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University
Angewandte Chemie - International Edition | Year: 2014

Cyclopentadienes are valuable intermediates in organic synthesis and also ubiquitous as the Cp ligands in organometallic chemistry. As part of ongoing efforts to develop novel organic reactions that employ functionalized alkynes, a [3+2] cycloaddition of propargylic alcohols and ketene dithioacetals has been developed, which leads to fully substituted 2,5-dialkylthio cyclopentadienes in good to excellent yields. In an unusual dethiolating Diels-Alder reaction, the cyclopentadienes were further reacted with maleimides to afford a family of novel fluorescent polycyclic compounds. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen X.,Nankai University | Dai W.,Central University of Finance and Economics
International Journal of Fuzzy Systems | Year: 2011

The concept of uncertain entropy is used to provide a quantitative measurement of the uncertainty associated with uncertain variables. After introducing the definition, this paper gives some examples of entropy of uncertain variables. Furthermore this paper proposes the maximum entropy principle for uncertain variables, that is, out of all the uncertainty distributions satisfying given constraints, to choose the one has maximum entropy. © 2011 TFSA.

We consider the Schrödinger-Poisson system: -ε2Δu + V(x)u + φ(x)u = f (u),-Δφ = u2 in R3, where the nonlinear term f is of critical growth. In this paper, we construct a solution (uε, φε) of the above elliptic system, which concentrates at an isolated component of positive locally minimum points of V as ε → 0 under certain conditions on f. In particular, the monotonicity of f(s)/s3 and the so-called Ambrosetti-Rabinowitz condition are not required. © 2014 AIP Publishing LLC.

Song H.-L.,East China University of Science and Technology | Yuan K.,East China University of Science and Technology | Wu X.-Y.,East China University of Science and Technology | Wu X.-Y.,Nankai University
Chemical Communications | Year: 2011

Novel squaramides containing tertiary phosphine were developed as chiral bifunctional organic catalysts to promote the asymmetric intramolecular Morita-Baylis-Hillman reaction of ω-formyl-enones. The adducts were obtained in high yields with good-to-excellent enantioselectivity (up to 93% ee).

Wang Z.,Nankai University | Wang Z.,Hong Kong Baptist University | Szolnoki A.,Hungarian Academy of Sciences | Perc M.,University of Maribor
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

While worldwide census data provide statistical evidence that firmly link the population density with several indicators of social welfare, the precise mechanisms underlying these observations are largely unknown. Here we study the impact of population density on the evolution of public cooperation in structured populations and find that the optimal density is uniquely related to the percolation threshold of the host graph irrespective of its topological details. We explain our observations by showing that spatial reciprocity peaks in the vicinity of the percolation threshold, when the emergence of a giant cooperative cluster is hindered neither by vacancy nor by invading defectors, thus discovering an intuitive yet universal law that links the population density with social prosperity. © 2012 American Physical Society.

Wang Y.,Temple University | Deng X.,Temple University | Mancarella S.,Temple University | Hendron E.,Temple University | And 4 more authors.
Science | Year: 2010

Calcium signals, pivotal in controlling cell function, can be generated by calcium entry channels activated by plasma membrane depolarization or depletion of internal calcium stores. We reveal a regulatory link between these two channel subtypes mediated by the ubiquitous calcium-sensing STIM proteins. STIM1 activation by store depletion or mutational modification strongly suppresses voltage-operated calcium (CaV1.2) channels while activating store-operated Orai channels. Both actions are mediated by the short STIM-Orai activating region (SOAR) of STIM1. STIM1 interacts with CaV1.2 channels and localizes within discrete endoplasmic reticulum/plasma membrane junctions containing both CaV1.2 and Orai1 channels. Hence, STIM1 interacts with and reciprocally controls two major calcium channels hitherto thought to operate independently. Such coordinated control of the widely expressed CaV1.2 and Orai channels has major implications for Ca 2+ signal generation in excitable and nonexcitable cells.

Chang X.,Jilin University | Wang Z.-Q.,Nankai University | Wang Z.-Q.,Utah State University
Nonlinearity | Year: 2013

This paper focuses on the following scalar field equation involving a fractional Laplacian:(δ) αu = g(u) in ℝN, where N ≥ 2, α ∈ (0, 1), (?δ) α stands for the fractional Laplacian. Using some minimax arguments, we obtain a positive ground state under the general BerestyckiLions type assumptions. © 2013 IOP Publishing Ltd & London Mathematical Society.

Du M.,Tianjin Normal University | Li C.-P.,Tianjin Normal University | Wu J.-M.,Tianjin Normal University | Guo J.-H.,Tianjin Normal University | Wang G.-C.,Nankai University
Chemical Communications | Year: 2011

This work first demonstrates that the robust [Cu2(OOCR) 4] unit can be destroyed and reconstructed in the solid state, as observed in water-induced structural interconversion of two distinct coordination polymers with 5-bromonicotinate. © 2011 The Royal Society of Chemistry.

Chen R.,Fuzhou University | Xiang K.-N.,Nankai University
Journal of Combinatorial Theory. Series B | Year: 2012

In this paper, we prove that via an operation "reducing", every 3-connected representable matroid M with at least nine elements can be decomposed into a set of sequentially 4-connected matroids and three special matroids which we call freely-placed-line matroids, spike-like matroids and swirl-like matroids; more concretely, there is a labeled tree that gives a precise description of the way that M built from its pieces. © 2011.

Yin H.,Peking University | Wang T.,Peking University | Jiao N.,Peking University | Jiao N.,Nankai University
Organic Letters | Year: 2014

Copper-catalyzed oxoazidation and alkoxyazidation of indoles has been developed. The dearomatization reaction which leads to versatile 3-azido indolenine and oxindole derivatives in moderate to good yields could be used in a further transformation. © 2014 American Chemical Society.

Zhang X.,Nankai University | Liu J.,Hebei University of Technology
Journal of Agricultural and Food Chemistry | Year: 2011

The effect of arabic gum (AG) and xanthan gum (XG) on the physicochemical properties of 2% pesticide avermyctin in water emulsions was systematically investigated by measuring creaming stability, droplet size, zeta potential, and rheology. Addition of AG and XG had significant influence on the physicochemical properties of emulsions. Emulsions showed high stability throughout the storage time in the AG concentration range of 0-0.14%. In contrast, addition of XG induced the apparent creaming of emulsion as the XG concentration increased from 0.011 to 0.15%, which might be well explained by the depletion flocculation of droplets. The droplet diameter increased progressively with increasing AG concentration; however, it sharply grew initially with XG concentration and reached a maximum, followed by a gradual decrease. Zeta potential increased gradually as AG concentration was lower than 0.081%, followed by a slight decrease, whereas it reduced dramatically as XG concentration increased from 0.011 to 0.040% and then remained almost unchanged. In the AG concentration range of 0-0.14%, the emulsion exhibited typical Newtonian flow behavior and the viscosity decreased a little. The XG emulsion exhibited Newtonian flow behavior at low XG concentrations (′0.019%), whereas, non-Newtonian flow behavior was displayed at relatively high XG concentrations (>0.019%), wherein viscosity value and yield value increased gradually as XG concentration increased. In addition, the curves of shear stress versus shear rate for XG emulsion and solution were well fitted by a power law model and the Herschel-Bulkley model; the Herschel-Bulkley model fitted much better. The present study would provide useful information for the reasonable application of AG and XG in making stable pesticide emulsion. © 2011 American Chemical Society.

Liu H.,Nankai University | Lalanne P.,ParisTech Optics Institute
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

As shown in a recent letter [Nature 452, 728 (2008)] with a microscopic model, the phenomenon of the extraordinary optical transmission (EOT) is intrinsically due to two distinct surface waves: the surface plasmon polariton and the quasi-cylindrical wave (quasi-CW) that efficiently funnel light into the hole aperture at resonance. Here we present a comprehensive microscopic model of the EOT that takes into account the two surface waves. The model preserves the desirable physical insight of the previous approach, but since it additionally takes into account the quasi-CWs, it provides highly accurate predictions over a much broader spectral range, from visible to microwave radiation. The net outcome is a complete understanding of many aspects of the EOT and especially of the role of the metal conductivity that has largely puzzled the initial interpretations. We believe that the main conclusions of the present analysis may be applied to many Wood-type surface resonances on metallic surfaces. © 2010 Optical Society of America.

Fang Z.,Northeast Normal University | Ning Y.,Northeast Normal University | Mi P.,Northeast Normal University | Liao P.,Northeast Normal University | And 2 more authors.
Organic Letters | Year: 2014

A copper(I)-catalyzed, regioselective C-H α-trifluoromethylation of α,β-unsaturated carbonyl compounds using Togni's reagent was developed. Diverse substrates, including enones as well as α,β- unsaturated esters, thioesters, and amides, stereospecifically afforded the corresponding (E)-α-trifluoromethylated products in moderate to high yields. Further, this method was applied to the C-H trifluoromethylation of drugs. © 2014 American Chemical Society.

Hou S.,South China University of Technology | Ou Z.,South China Normal University | Chen Q.,Nankai University | Wu B.,South China Normal University
Biosensors and Bioelectronics | Year: 2012

A novel acetylcholinesterase (AChE)/choline oxidase (ChOx) bienzyme amperometric acetylcholine biosensor based on gold nanoparticles (AuNPs) and multi-walled carbon nanotubes (MWCNTs) has been successfully developed by self-assembly process in combination of sol-gel technique. A thiolated aqueous silica sol containing MWCNTs and ChOx was first dropped on the surface of a cleaned Pt electrode, and then AuNPs were assembled with the thiolated sol-gel network. Finally, the alternate deposition of poly (diallyldimethylammonium chloride) (PDDA) and AChE was repeated to assemble different layers of PDDA-AChE on the electrode for optimizing AChE loading. Among the resulting biosensors, the biosensor based on two layers of PDDA-AChE multilayer films showed the best performance. It exhibited a wide linear range, high sensitivity and fast amperometric response, which were 0.005-0.4. mM, 3.395 μA/mM, and within 15. s, respectively. The biosensor showed long-term stability and acceptable reproducibility. More importantly, this study could provide a simple and effective multienzyme immobilization platform for meeting the demand of the effective immobilization enzyme on the electrode surface. © 2011 Elsevier B.V.

He Z.,Wuhan University | Liu T.,Wuhan University | Tao H.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Organic Letters | Year: 2012

Facile access to enantioenriched isoindolines bearing a quaternary stereogenic center and a tertiary stereogenic center was successfully developed via highly efficient Cu(I)/(S,Rp)-PPFOMe-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide with quinone derivatives followed by silica-gel-promoted aromatization in a one-pot reaction protocol. The present catalytic system exhibited high diastereoselectivity, excellent enantioselectivity, and a broad substrate scope under mild conditions. © 2012 American Chemical Society.

Zhao P.,Tsinghua University | Yan X.,Tsinghua University | Yin H.,Tsinghua University | Xi C.,Tsinghua University | Xi C.,Nankai University
Organic Letters | Year: 2014

The reaction of arylisothiocyanate, alkyltriflate, and alkynes leads to variously substituted quinolines in high yields. The reaction undergoes alkyltriflate-triggered domino electrophilic activation and avoids the use of a transition-metal catalyst. A variety of functional groups are tolerated in the quinoline ring. © 2014 American Chemical Society.

Li M.,Qingdao University of Science and Technology | Li M.,Nankai University | Lv X.-L.,Qingdao University of Science and Technology | Wen L.-R.,Qingdao University of Science and Technology | Hu Z.-Q.,Qingdao University of Science and Technology
Organic Letters | Year: 2013

A novel efficient one-pot four-component regioselective synthesis of pyrrolo[1,2-a][1,10]phenanthrolines in excellent yields has been developed by 1,3-dipolar cycloaddition of aldehydes, malononitrile, and isocyanides with 1,10-phenanthroline under solvent-free conditions within 3 min without using any catalyst or activation. The products were preliminarily investigated as chromogenic and fluorescent sensors for Cu2+ ions. © 2013 American Chemical Society.

Dai W.,Central University of Costa Rica | Chen X.,Nankai University
Mathematical and Computer Modelling | Year: 2012

Uncertainty theory is a branch of mathematics of studying the subjective uncertain behavior. Entropy is a key concept which provides a quantitative measurement of the uncertainty associated with uncertain variables. In order to compute the entropy more conveniently, this paper proposes some formulas of entropy of function of uncertain variables with regular uncertain distributions. Furthermore, the positive linearity property of the entropy operator is proved immediately following from these formulas at last. © 2011.

Zou C.,Nankai University | Tsung F.,Hong Kong University of Science and Technology
Journal of Quality Technology | Year: 2010

Nonparametric or distribution-free charts are useful in statistical process control when thereis a lack of or limited knowledge about the underlying process distribution. Most existing approachesin the literature are for monitoring location parameters. They may not be effective with a change of distribution over time in many applications. This paper develops a new distribution-free control chart based on the integration of a powerful nonparametric goodness-of-fit test and the exponentially weighted moving-average (EWMA)control scheme. Benefiting from certain desirable properties of the test and the proposed charting statistic,our proposed control chart is computationally fast, convenient to use, and efficient in detecting potential shifts in location, scale, and shap Thus, it offers robust protection against variation in various underlying distributions. Numericalstudies and a real-data example show that the proposed approaches are quite effective in industrialapplications, particularly in start-up and short-run situations.

Li X.,CAS Beijing National Laboratory for Molecular | Luo S.,CAS Beijing National Laboratory for Molecular | Cheng J.-P.,Nankai University
Chemistry - A European Journal | Year: 2010

Chiral pyrroloindoles: A highly enantioselective catalytic conjugate addition of 3-substituted oxindoles with 2-chloroacrylonitrile has been developed with a readily accessible alkyl bifunctional tertiary amine thiourea catalyst. Excellent stereoselectivity of up to >30:1 diastereomeric ratio and 99% enantiomeric excess was achieved. The obtained Michael products could be easily converted to chiral pyrroloindole structures, which are widely distributed in natural indole alkaloids (see scheme). Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fang L.,Nankai University | Li H.,Qinghai Normal University
Computers and Operations Research | Year: 2013

The calculation of cost efficiency requires complete and accurate information on the input prices at each decision making unit (DMU). In practice, however, exact knowledge of the relevant prices is difficult to come by, and prices may be subject to variation in the short term. To estimate the cost efficiency while taking price uncertainty into account, cone-ratio DEA models incorporating the available price information as weight restrictions can be applied. However, the literature lacks a clear explanation regarding the exact relationships between these two models. In this paper, through a duality study, we establish both the theoretical properties of these relationships and the characteristics of their efficiency solutions between cone-ratio DEA models and CE models, assuming there are imprecise price data. Based on the duality study, we also develop a new approach and design a lexicographic order algorithm to estimate the lower bounds of the cost efficiency measure. Our computational experiments indicate that the proposed models are robust and that the proposed algorithm is computationally simple. © 2012 Elsevier Ltd. All rights reserved.

Shan J.,Nankai University | Zhu K.,Chinese University of Hong Kong
Production and Operations Management | Year: 2013

With the outsourcing of manufacturing activities from Western countries, China has gradually become the global manufacturing hub. In the presence of increased competition from both inside and outside of China, many Chinese manufacturers have turned to scientific management approaches and implemented various enterprise systems. In academia, there has been a growing interest in quantifying the impacts of such efforts on the corporate performance of Chinese firms, and research has been carried out in areas such as finance and accounting. However, due to limited visibility of operational decisions and data, there seems to be a lack of investigation into the impacts on the firms' operational performance in the literature. In this article, we apply an empirical method to investigate the inventories of 1286 firms listed on the two stock exchanges in China, the Shanghai Stock Exchange and the Shenzhen Stock Exchange. We find that on average the inventory levels have declined over time and that the firm-level data is consistent with several implications derived from classical inventory models. © 2012 Production and Operations Management Society.

Chen X.,Nankai University | Gao J.,Renmin University of China
Soft Computing | Year: 2013

Term structure models describe the evolution of the yield curve through time, without considering the influence of risk, tax, etc. Recently, uncertain processes were initialized and applied to option pricing and currency model. Under the assumption of short interest rate following uncertain processes, this study investigates the term-structure equation. This equation is first derived for valuing zero-coupon bond. Finally, analytic solutions of the uncertain interest rate equation are given when the process of interest rate is assumed to be the uncertain counterparts of the Ho-Lee model and Vasicek model, respectively. © 2012 Springer-Verlag.

Chen X.,Nankai University | Liu Y.,Tsinghua University | Ralescu D.A.,University of Cincinnati
Fuzzy Optimization and Decision Making | Year: 2013

This paper presents an uncertain stock model with periodic dividends based on uncertainty theory. Some option pricing formulae related to the proposed model are investigated and several numerical examples are discussed to illustrate the related formula. © 2012 Springer Science+Business Media New York.

Fang X.,Wuhan University | Li J.,Wuhan University | Tao H.-Y.,Wuhan University | Wang C.-J.,Wuhan University | Wang C.-J.,Nankai University
Organic Letters | Year: 2013

An effective diastereoselective [3 + 3] cycloaddition of 1,4-dithiane-2,5-diol with azomethine imines catalyzed by DABCO is described. A variety of highly functionalized six-membered dinitrogen-fused heterocycles can be obtained in good yield with excellent diastereoselectivity, which was controlled by anomeric effect. © 2013 American Chemical Society.

The new energy industry is a complex system and its normal operation needs strong, stable and l asting driving forces. The driving forces contain technology progress, market demand, construction of industry chain, government policy and development environment. Technology progress, market demand and construction of industry chain constitute the inner driving force system, while government policy and development environment constitute the external driving force system. These two driving force systems and the harmonious cooperation between them constitute driving force mechanism. The perfect driving force mechanism is the important condition to encourage new energy industry. © 2011 Published by Elsevier Ltd.

Liu Z.-B.,Hong Kong Polytechnic University | Liu Z.-B.,Nankai University | He X.,Hong Kong Polytechnic University | Wang D.N.,Hong Kong Polytechnic University
Optics Letters | Year: 2011

We demonstrate a nanosecond-pulse erbium-doped fiber laser that is passively mode locked by a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution. Owing to the good solution processing capability of few-layered graphene oxide, which can be filled into the core of a hollow-core photonic crystal fiber through a selective hole filling process, a graphene saturable absorber can be successfully fabricated. The output pulses obtained have a center wavelength, pulse width, and repetition rate of 1561:2nm, 4:85 ns, and 7:68MHz, respectively. This method provides a simple and efficient approach to integrate the graphene into the optical fiber system. © 2011 Optical Society of America.

Tian L.,Tianjin Normal University | Chen Z.,Nankai University
Inorganic Chemistry Communications | Year: 2011

Using a flexible bis-triazole ligand 1,4-bis(1,2,4-triazol-1-y1)butane (btrb), two new copper(II) compounds [Cu0.5(btrb)0.5Cl] n (1) and [Cu0.5(btrb)Cl]n (2), have been isolated. Conformations of btrb can be tuned as a result of changing the metal/ligand ratio in the reaction system, which ultimately forms two novel framework structures. 1 is a three dimensional network with CdSO4 topology, and uncommonly six-fold Cl...H-C hydrogen bonds reside in the 3D framework. 2 possesses 2D (4.4) net framewok. Triple Cl...H-C hydrogen bonds reside among the 2D layers, which link the 2D layers to lead to a 3D supramolecular architecture. For 1 and 2, elemental analysis, thermal stability and EPR spectra have been carried out, and the conformational variation of btrb also has been discussed. © 2011 Elsevier B.V. All rights reserved.

Sun J.-P.,Beijing Normal University | Li L.-C.,Nankai University | Zheng X.-J.,Beijing Normal University
Inorganic Chemistry Communications | Year: 2011

A cubane-like tetranuclear nickel(II) compound [Ni4(L) 4Cl4(H2O)3(C2H 5OH)]·H2O (1) and a binuclear iron(III) compound Fe2(L)2Cl4 (2) (HL = 2-pyridinemethanol) have been prepared by solvothermal reaction of metal chloride and 2-pyridinecarboxaldehyde in C2H5OH, in which 2-pyridinecarboxaldehyde was in situ reduced to 2-pyridinemethanol. The single crystal X-ray diffraction analysis suggests that the cluster core of [Ni 4(μ3-O)4] in 1 is formed by four Ni(II) and four alkoxide oxygen atoms at alternating corners, and the binuclear iron complex 2 is almost co-planar structure with alkoxide oxygen atom in μ2-mode. The magnetic studies reveal the ferromagnetic behavior for 1 and the anti-ferromagnetic interaction for 2. © 2011 Elsevier B.V.

This study investigates the effect of native language (Mandarin Chinese) on the use of English discourse markers by L1 Chinese speakers of English. Few previous studies have been conducted on this area. Data for the study were gathered using individual sociolinguistic interviews with five native English speakers and ten L1 Chinese speakers. Results show that three Chinese discourse markers were found to have some influence on their corresponding English expressions. The L1 Chinese speakers using the deliberative function of I think in medial or final position (while the native English speakers did not) may have transferred their use of I think from their L1 wo juede because wo juede can mark the deliberative meaning in medial or final position. Second, the L1 Chinese speakers used yeah/yes as a backchannel after the interlocutor's reaction " uh huh" or " ok" while the native English speakers did not. This use may be transferred from the corresponding Chinese expression dui because dui was found to have the same use in the data. Finally, ah was found to perform a clause-medial function (followed by self-correction) by the L1 Chinese speakers; however, the native English speakers did not use ah for that function. The corresponding Chinese expression a was found to have the same correction function. © 2012 Elsevier B.V.

Yanga M.-Z.,Nankai University
European Physical Journal C | Year: 2012

With the decay constants of D and Ds mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in B and D mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of B and D mesons are obtained. Both the masses and decay constants obtained here can be seen as consistent with the experimental data. The wave functions can be used in the study of B and D meson decays. © Springer-Verlag / Società Italiana di Fisica 2012.

Wei J.,PLA Military Transportation University | Govindan K.,University of Southern Denmark | Li Y.,Nankai University | Zhao J.,Tianjin Polytechnic University
Computers and Operations Research | Year: 2015

The optimal decision problem of a closed-loop supply chain with symmetric and asymmetric information structures is considered using game theory in this paper. The paper aims to explore how the manufacturer and the retailer make their own decisions about wholesale price, retail price, and collection rate under symmetric and asymmetric information conditions. Four game models are established, which allow one to examine the strategies of each firm and explore the role of the manufacturer and the retailer in four different game scenarios under symmetric and asymmetric information structures. The optimal strategies in closed form are given under the decision scenarios with symmetric information; moreover, the first order conditions that the optimal retail price, optimal wholesale price, and optimal collection rate satisfy are given under the decision scenarios with asymmetric information. The results obtained under symmetric and asymmetric information conditions and some key model parameters used in this paper are analyzed using a numerical approach by which some managerial analysis are given. © 2013 Elsevier Ltd. All rights reserved.

Peisley A.,Harvard University | Wu B.,Harvard University | Yao H.,Program in Cellular and Molecular Medicine | Yao H.,Nankai University | And 3 more authors.
Molecular Cell | Year: 2013

Retinoic acid-inducible gene 1 (RIG-I) and melanomadifferentiation-associated protein 5 (MDA5) are paralogous receptors for viral double-stranded RNA (dsRNA) with divergent specificity. We have previously shown that MDA5 forms filaments upon viral dsRNA recognition and that this filament formation is essential for interferon signal activation. Here, we show that while RIG-I binds to a dsRNA end as a monomer in the absence of ATP, it assembles in the presence of ATP into a filament that propagates fromthe dsRNA end to the interior. Furthermore, RIG-I filaments directly stimulate mitochondrial antiviral signaling (MAVS) filament formation without any cofactor, such as polyubiquitin chains, and forced juxtaposition of the isolated signaling domain of RIG-I, as it would be in the filament, is sufficient to activate interferon signaling. Our findings thus define filamentous architecture as a common yet versatile molecular platform for divergent viral RNA detection and proximity-induced signal activation by RIG-I and MDA5. © 2013 Elsevier Inc.

Fang G.,Northeast Normal University | Bi X.,Northeast Normal University | Bi X.,Nankai University
Chemical Society Reviews | Year: 2015

Silver is a less expensive noble metal. Superior alkynophilicity due to π-coordination with the carbon-carbon triple bond makes silver salts ideal catalysts for alkyne-based organic reactions. This review highlights the progress in alkyne chemistry via silver catalysis primarily over the past five years (ca. 2010-2014). The discussion is developed in terms of the bond type formed with the acetylenic carbon (i.e., C-C, C-N, C-O, C-Halo, C-P and C-B). Compared with other coinage metals such as Au and Cu, silver catalysis is frequently observed to be unique. This critical review clearly indicates that silver catalysis provides a significant impetus to the rapid evolution of alkyne-based organic reactions, such as alkynylation, hydrofunctionalization, cycloaddition, cycloisomerization, and cascade reactions. © The Royal Society of Chemistry.

Wang L.,Nankai University
Sub-Cellular Biochemistry | Year: 2010

The O antigen, consisting of many repeats of an oligosaccharide unit, is part of the lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria. It is on the cell surface and appears to be a major target for both immune system and bacteriophages, and therefore becomes one of the most variable cell constituents. Th