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Nanjing, China

Nanjing University , or Nanking University, is one of the oldest and most prestigious institutions of higher learning in China. Following many changes through dynasties since CE 258, it was established as a modern school in 1902 in late Qing dynasty, and became a modern university in the early 1920s, the early years of Republic of China, being the first Chinese modern university with the combination of education and research, and also as a pioneer laying the foundations for the establishment of the modern educational system in China. Before the eve of establishment of People's Republic of China in 1949, the name was changed from National Central University to Nanjing University.Nanjing University is a comprehensive research university. It is a member of the C9 League and Yangtze Delta Universities Alliance. NJU is a national university directly under the Ministry of Education of China, largely financed by the national and the Jiangsu provincial governments. Nanjing University has two campuses: Gulou campus, located in the centre of Nanjing, and Xianlin campus, located in northeast of Nanjing south of the Yangtze River, which is the home to most undergraduate students and graduate students of several departments. Wikipedia.

Wu X.,CAS Chengdu Institute of Biology | Duffy J.E.,Virginia Institute of Marine Science | Reich P.B.,University of Minnesota | Sun S.,CAS Chengdu Institute of Biology | Sun S.,Nanjing University
Ecological Monographs | Year: 2011

Top-down control has been extensively documented in food webs based on living plants, where predator limitation of herbivores can cascade to facilitate plant growth (the green-world hypothesis), particularly in grasslands and aquatic systems. Yet the ecosystem role of predators in detrital food webs is less explored, as is the potential effect of climate warming on detritus-based communities. We here show that predators have a "brown-world" role in decomposer communities via a cascading top-down control on plant growth, based on the results of an experiment that factorially manipulated presence and size of two predator species as well as temperature (warmed vs. unwarmed). The inclusion of predatory beetles significantly decreased abundance of coprophagous beetles and thus the rate of dung decomposition and productivity of plants growing surrounding the dung. Moreover, the magnitude of these decreases differed between predator species and, for dung loss, was temperature dependent. At ambient temperature, the larger predators tended to more strongly influence the dung loss rate than did the smaller predators; when both predators were present, the dung loss rate was higher relative to the treatments with the smaller predators but comparable to those with the larger ones, suggesting an antagonistic effect of predator interaction. However, warming substantially reduced dung decomposition rates and eliminated the effects of predation on dung decomposition. Although warming substantially decreased dung loss rates, warming only modestly reduced primary productivity. Consistent with these results, a second experiment exploring the influence of the two predator species and warming on dung loss over time revealed that predatory beetles significantly decreased the abundance of coprophagous beetles, which was positively correlated with dung loss rates. Moreover, experimental warming decreased the water content of dung and hence the survival of coprophagous beetles. These results confirm that the "brown-world" effect of predator beetles was due to cascading top-down control through coprophagous beetles to nutrient cycling and primary productivity. Our results also highlight potentially counterintuitive effects of climate warming. For example, global warming might significantly decrease animalmediated decomposition of organic matter and recycling of nutrients in a future warmed world. © 2011 by the Ecological Society of America.

Sun Y.,Nanjing University | Wang C.,CAS Academy of Mathematics and Systems Science | Zhang Z.,Peking University
Archive for Rational Mechanics and Analysis | Year: 2011

We prove a blow-up criterion in terms of the upper bound of (ρ, ρ-1, θ) for a strong solution to three dimensional compressible viscous heat-conductive flows. The main ingredient of the proof is an a priori estimate for a quantity independently introduced in Haspot (Regularity of weak solutions of the compressible isentropic Navier-Stokes equation, arXiv:1001. 1581, 2010) and Sun et al. (J Math Pure Appl 95:36-47, 2011), whose divergence can be viewed as the effective viscous flux. © 2011 Springer-Verlag.

Wang R.,Nanjing University
Molecular medicine (Cambridge, Mass.) | Year: 2012

Resistance to docetaxel (DTX) usually occurs in patients with lung adenocarcinoma. To better elucidate the underlying molecular mechanisms involved in resistance to DTX-based chemotherapy, we established a DTX-resistant lung adenocarcinoma cell line (SPC-A1/DTX). By gene array analysis, the expression of ING4 was found to be significantly downregulated in SPC-A1/DTX cells. Additionally, the decreased expression of the ING4 gene was induced upon DTX treatment of SPC-A1 cells. Overexpression of ING4 reverses DTX or paclitaxel resistance of DTX-resistant lung adenocarcinoma cells (SPC-A1/DTX or A549/Taxol) by inducing apoptosis enhancement and G2/M arrest, and small interfering RNA-mediated ING4 knockdown renders DTX-sensitive lung adenocarcinoma cells more resistant to DTX or paclitaxel. Also, overexpression of ING4 could enhance the in vivo sensitivity of SPC-A1/DTX cells to DTX. The phenotypical changes of SPC-A1/DTX cells induced by overexpression of ING4 might be associated with the decreased ratio of Bcl-2/Bax, which resulted in the activation of caspase-3. The level of ING4 expression in tumors of nonresponding patients was significantly lower than that in those of responders, suggesting that the expression of ING4 was positively correlated with tumor response to DTX. Our results provide the first evidence that ING4 might be essential for DTX resistance in lung adenocarcinoma. Thus, ING4 will be a potential molecular target for overcoming resistance to DTX-based chemotherapies in lung adenocarcinoma.

In this paper, we mainly show the following two statements. A discrete-time topological Markovian jump linear system is uniformly exponentially stable if and only if it is robustly periodically stable, by using a Gel'fand-Berger-Wang formula proved here.A random linear ODE driven by a semiflow with closing by periodic orbits property is uniformly exponentially stable if and only if it is robustly periodically stable, by using a perturbation technique of Shantao Liao and the semi-uniform ergodic theorems.Our proofs involve the ergodic theory in both of the above two cases. In addition, counterexamples are constructed to the robustness condition and to the spectral finiteness of linear cocycle. © 2014 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Xie J.-W.,Nanjing University | Xie J.-W.,University of Toronto
Astrophysical Journal | Year: 2014

Many multiple-planet systems have been found by the Kepler transit survey and various radial velocity (RV) surveys. Kepler planets show an asymmetric feature, namely, there are small but significant deficits/excesses of planet pairs with orbital period spacing slightly narrow/wide of the exact resonance, particularly near the first order mean motion resonance (MMR), such as 2:1 and 3:2 MMR. Similarly, if not exactly the same, an asymmetric feature (pileup wide of 2:1 MMR) is also seen in RV planets, but only for massive ones. We analytically and numerically study planets' orbital evolutions near and in the MMR. We find that their orbital period ratios could be asymmetrically distributed around the MMR center regardless of dissipation. In the case of no dissipation, Kepler planets' asymmetric orbital distribution could be partly reproduced for 3:2 MMR but not for 2:1 MMR, implying that dissipation might be more important to the latter. The pileup of massive RV planets just wide of 2:1 MMR is found to be consistent with the scenario that planets formed separately then migrated toward the MMR. The location of the pileup infers a K value of 1-100 on the order of magnitude for massive planets, where K is the damping rate ratio between orbital eccentricity and semimajor axis during planet migration. © 2014. The American Astronomical Society. All rights reserved.

Wang C.,University of Macau | Dong L.,Nanjing University
Trends in Biotechnology | Year: 2015

A biological system is essentially an elegant assembly of polymeric nanostructures. The polymers in the body, biomacromolecules, are both building blocks and versatile messengers. We propose that non-biologically derived polymers can be potential therapeutic candidates with unique advantages. Emerging findings about polycations, polysaccharides, immobilised multivalent ligands, and biomolecular coronas provide evidence that polymers are activated at the nano-bio interface, while emphasising the current theoretical and practical challenges. Our increasing understanding of the nano-bio interface and evolving approaches to establish the therapeutic potential of polymers enable the development of polymer drugs with high specificities for broad applications. © 2014 Elsevier Ltd.

Jiang S.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Ju Q.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Li F.,Nanjing University
Communications in Mathematical Physics | Year: 2010

This paper is concerned with the incompressible limit of the compressible magnetohydrodynamic equations with periodic boundary conditions. It is rigorously shown that the weak solutions of the compressible magnetohydrodynamic equations converge to the strong solution of the viscous or inviscid incompressible magnetohydrodynamic equations as long as the latter exists both for the well-prepared initial data and general initial data. Furthermore, the convergence rates are also obtained in the case of the well-prepared initial data. © 2010 Springer-Verlag.

Sun S.,Nanjing University | Sun S.,CAS Chengdu Institute of Biology | Frelich L.E.,University of Minnesota
Journal of Ecology | Year: 2011

1.We hypothesize that flowering phenology correlates with plant height growth pattern and that the pattern is associated with functional traits including maximum plant height (Hmax), RGR, stem tissue mass density (SD), hollow ratio (proportion of central hollow of stem cross-sectional area) and leaf mass per area (LMA) in grassland herbaceous species. 2.We investigated plant height growth trajectories and flower phenology, and measured LMA, SD and hollow ratio for 25 herbaceous species including 20 dicot forb species and five monocot species in an old-field grassland of New England, USA. Hmax, RGR, T10 and T90 (Julian day when plant height was 10% and 90%Hmax respectively) were derived from a logistic function for each species and were analysed in relation to LMA and SD. 3.Hmax was positively correlated with T10, T90 and flowering onset time (Julian day when the first 10% of flowers were blossoming) across species and across evolutionary-correlated divergences. Early growing and flowering species were shorter than late ones, and species reaching Hmax earlier flowered earlier than their counterparts. 4.There was a positive relationship between T90 and RGR, in which early growing species were usually at mid-to-high levels of RGR, while late-growing ones had widely varied RGR. A similar relationship was found between flowering onset time and RGR. RGR was significantly negatively correlated with SD and LMA but positively with hollow ratio, as indicated by correlation analysis and phylogenetically independent comparative analysis. 5.Based on the above results, we propose that herbaceous species have two major dimensions of height growth strategies (early vs. late and fast vs. slow growth), collectively resulting in three extreme cases (early and fast, late and slow, and late and fast). Different height growth trajectories resulting from these strategies may reduce asymmetric competition among co-existing species in dense grasslands. 6.Synthesis. Flowering phenology and height growth patterns are significantly associated with functional traits such as RGR, LMA and hollow ratio in herbaceous grassland species. The difference in height growth trajectories and associated functional traits may allow species coexistence possibly at both plant and consumer trophic levels. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society.

Qian Y.,Pacific Northwest National Laboratory | Huang M.,Pacific Northwest National Laboratory | Yang B.,Nanjing University | Berg L.K.,Pacific Northwest National Laboratory
Journal of Hydrometeorology | Year: 2013

In this study, the authors incorporate an operational-like irrigation scheme into the Noah land surface model as part of the Weather Research and Forecasting Model (WRF). A series of simulations, with and without irrigation, is conducted over the Southern Great Plains (SGP) for an extremely dry (2006) and wet (2007) year. The results show that including irrigation reduces model bias in soil moisture and surface latent heat (LH) and sensible heat (SH) fluxes, especially during a dry year. Irrigation adds additional water to the surface, leading to changes in the planetary boundary layer. The increase in soil moisture leads to increases in the surface evapotranspiration and near-surface specific humidity but decreases in the SH and surface temperature. Those changes are local and occur during daytime. There is an irrigation-induced decrease in both the lifting condensation level (ZLCL) and mixed-layer depth. The decrease in ZLCL is larger than the decrease in mixed-layer depth, suggesting an increasing probability of shallow clouds. The simulated changes in precipitation induced by irrigation are highly variable in space, and the average precipitation over the SGP region only slightly increases. A high correlation is found among soil moisture, SH, and ZLCL. Larger values of soil moisture in the irrigated simulation due to irrigation in late spring and summer persist into the early fall, suggesting that irrigation-induced soil memory could last a few weeks to months. The results demonstrate the importance of irrigation parameterization for climate studies and improve the process-level understanding on the role of human activity in modulating land-air-cloud interactions. © 2013 American Meteorological Society.

Water plays an important role in the ductile deformation and evolution of the upper mantle. Water contents of natural olivine from 240 samples reveal a wide variation of 0-170ppm H2O, suggesting heterogeneous water distribution in the continental upper mantle. The average water contents (17±13ppm H2O) in kimberlite nodules provide the best estimation of water concentrations in olivine in the lithosphere beneath cratons. The very low water contents (7±9ppm H2O) of olivine from basalt xenoliths are caused by significant hydrogen loss during transport, while the high values (44±34ppm H2O) in olivine megacrysts from kimberlites reflect restricted fluid-rich conditions in the upper mantle. To compare deformation in different tectonic environments, the western Superior Province (Canada), the Dabie Mountains and the North Jiangsu basin (China) are selected to represent an Archean craton, an orogenic belt and a rift basin, respectively. Using recent flow laws of olivine, deformation maps of dry and wet olivine are constructed under P-T conditions of the three tectonic units and in a continental subduction zone characterized by P=6.28GPa and T=900°C. For dry olivine, diffusion creep is the dominant mechanism in all the cases, which is contrary to the widely observed crystal preferred orientation of olivine in peridotites and seismic anisotropy observations. For wet olivine, only a small amount of water (50H/106Si) can remarkably decrease the stress of dislocation creep and increase contribution of dislocation creep to the deformation of olivine. The strain rate profiles of olivine indicate a transition from dislocation creep to diffusion creep at a depth of ~220km, which can be related with the Lehmann discontinuity characterized by a rapid decrease in seismic anisotropy. However, the pressure-induced fabric transition from [100] slip to [001] slip may be responsible for the Lehmann discontinuity in subduction zones. Therefore rheology of the continental upper mantle is controlled by power-law creep of wet olivine, and diffusion creep is the dominant deformation mechanism in the deep upper mantle, especially for fine-grained peridotites. The mechanical lithosphere-asthenosphere boundary (LAB) can be defined by the characteristic pressure derivative of effective viscosity. The sharp LAB beneath the Dabie Mountains and the Sulu terrane favors the lithosphere-asthenosphere decoupling, while the diffuse LAB beneath the western Superior Province will protect the continental root from convective erosion and mantle metasomatism. The long-term preservation of the continental roots can be attributed to a large viscosity contrast (temperature contrast) at a depth of <150km, and a thick and diffuse LAB at a depth of >150km. © 2010 Elsevier B.V.

Zhao Y.,Nanjing University | Zhang J.,Jiangsu Academy of Environmental Sciences | Nielsen C.P.,Harvard University
Atmospheric Chemistry and Physics | Year: 2013

To examine the effects of China's national policies of energy conservation and emission control during 2005-2010, inter-annual emission trends of gaseous pollutants, primary aerosols, and CO2 are estimated with a bottom-up framework. The control measures led to improved energy efficiency and/or increased penetration of emission control devices at power plants and other important industrial sources, yielding reduced emission factors for all evaluated species except NOx. The national emissions of anthropogenic SO2, CO, and total primary PM (particulate matter) in 2010 are estimated to have been 89%, 108%, and 87% of those in 2005, respectively, suggesting successful emission control of those species despite fast growth of the economy and energy consumption during the period. The emissions of NOx and CO2, however, are estimated to have increased by 47% and 43%, respectively, indicating that they remain largely determined by the growth of energy use, industrial production, and vehicle populations. Based on application of a Monte-Carlo framework, estimated uncertainties of SO2 and PM emissions increased from 2005 to 2010, resulting mainly from poorly understood average SO2 removal efficiency in flue gas desulfurization (FGD) systems in the power sector, and unclear changes in the penetration levels of dust collectors at industrial sources, respectively. While emission trends determined by bottom-up methods can be generally verified by observations from both ground stations and satellites, clear discrepancies exist for given regions and seasons, indicating a need for more accurate spatial and time distributions of emissions. Limitations of current emission control polices are analyzed based on the estimated emission trends. Compared with control of total PM, there are fewer gains in control of fine particles and carbonaceous aerosols, the PM components most responsible for damages to public health and effects on radiative forcing. A much faster decrease of alkaline base cations in primary PM than that of SO2 may have raised the acidification risks to ecosystems, indicating further control of acid precursors is required. Moreover, with relatively strict controls in developed urban areas, air pollution challenges have been expanding to less-developed neighboring regions. There is a great need in the future for multi-pollutant control strategies that combine recognition of diverse environmental impacts both in urban and rural areas with emission abatement of multiple species in concert. © Author(s) 2013.

Wang L.J.,Nanjing University
Zhongguo zhen jiu = Chinese acupuncture & moxibustion | Year: 2011

To compare the therapeutic effect differences of chronic functional constipation treated with the combined therapy of grain-shaped moxibustion and acupuncture and simple acupuncture therapy. One hundred cases of constipation were randomly divided into an acupuncture and moxibustion group and an acupuncture group by fifty-fifty. Both groups were treated by acupuncture therapy with acupoints of two groups alternatively. Group 1: Tianshu (ST 25), Daheng (SP 15), Qihai (CV 6), Guanyuan (CV 4), Zusanli (ST 36), Shangjuxu (ST 37) and Sanyinjiao (SP 6). Group 2: Zhongliao (BL 33), Xialiao (BL 34), Dachangshu (BL 25), Shenshu (BL 23) and Pishu (BL 20). In acupuncture group, all the acupoints, were punctured; in acupuncture and moxibustion group, grain-shaped moxibustion was given at Qihai (CV 6), Susanli (ST 36), Dachangshu (BL 25) and Pishu (BL 20), and others were treated by puncture. The clinical therapeutic effect, and the changes of clinical score of constipation, quality of life and psychological symptoms score were observed before and after treatment. The total effective rate in acupuncture and moxibustion group was 74.0% (37/50), superior to that (52.0%, 26/50) in acupuncture group (P < 0.05). The clinical score of constipation, the quality of life and psychological symptoms score in both groups improved after treatment; in clinical score of constipation, the improvement of difficulty of defecation, defecation time, abdominal pain, exsufflation difficulty, endless sensation of defecation, obstruction sense of anus, purgative prescription dependence, quality of life score and psychological symptoms score in acupuncture and moxibustion group were superior to those in acupuncture group (P < 0.05, P < 0.01). For treating chronic functional constipation, the combined therapy of both grain-shaped moxibustion and acupuncture is safe and effective, superior to the simple acupuncture therapy.

Zhang L.,Nanjing University
Digestive diseases and sciences | Year: 2014

Infected pancreatic necrosis (IPN) and multiple organ dysfunction syndrome (MODS) are major complications of acute pancreatitis which determine disease severity and outcome. The aim of this study is to investigate the value of admission heart rate variability as a marker of IPN or MODS in severe acute pancreatitis (SAP) patients. Forty-one SAP patients within 72 h of symptoms onset were included in this prospective observational study. General demographics, laboratory data and the acute physiology and chronic health evaluation (APACHE) II scores were recorded at admission. 5-minute ECG signals were obtained at the same time for heart rate variability analyses to assess SAP severity. The baseline heart rate variability measurements, levels of low frequency/high frequency (LF/HF) were significantly lower whereas high frequency norm (nHF) levels were significantly higher in patients who present with IPN and MODS or died (P < 0.01). Low frequency (LF) levels were lower in patients who present with IPN or MODS as compared to patients without these complications. Levels of low frequency norm (nLF) were lower in MODS and non-survival patients. nHF and LF/HF were good predictors of IPN and MODS, superior to procalcitonin. nHF and LF/HF were better than APACHE II in predicting IPN and LF/HF showed superiority over APACHE II in the prediction of MODS. Admission heart rate variability is a good marker of IPN and MODS in SAP patients.

Zhang Z.-Y.,Nanjing University
Journal of Physics Condensed Matter | Year: 2011

The quantum anomalous Hall (QAH) effect in kagomé lattices is investigated in the presence of both Rashba spinorbit coupling and an exchange field. In addition to the gap at the Dirac points as found in graphene, a new topological energy gap is opened at the point. With the Fermi energy lying in the first gap, the Chern number =2 as in graphene, whereas with it lying in the second one, =1. The distribution of Berry curvature is obtained to reveal the nontrivial topological properties in momentum space. For stripes with armchair and zigzag edges, the topological characteristics of gapless edge states on the genus g=2 Riemann surface are studied. The obtained nonzero winding numbers also demonstrate the QAH effect. © 2011 IOP Publishing Ltd.

Liu F.T.,Monash University | Ting K.M.,Monash University | Zhou Z.-H.,Nanjing University
ACM Transactions on Knowledge Discovery from Data | Year: 2012

Anomalies are data points that are few and different. As a result of these properties, we show that, anomalies are susceptible to a mechanism called isolation. This article proposes a method called Isolation Forest (iForest), which detects anomalies purely based on the concept of isolation without employing any distance or density measure-fundamentally different from all existing methods. As a result, iForest is able to exploit subsampling (i) to achieve a low linear time-complexity and a small memory-requirement and (ii) to deal with the effects of swamping and masking effectively. Our empirical evaluation shows that iForest outperforms ORCA, one-class SVM, LOF and Random Forests in terms of AUC, processing time, and it is robust against masking and swamping effects. iForest also works well in high dimensional problems containing a large number of irrelevant attributes, and when anomalies are not available in training sample. © 2012 ACM 1556-4681/2012/03-ART3 $10.00.

Lane L.A.,Georgia Institute of Technology | Qian X.,Georgia Institute of Technology | Smith A.M.,University of Illinois at Urbana - Champaign | Nie S.,Georgia Institute of Technology | Nie S.,Nanjing University
Annual Review of Physical Chemistry | Year: 2015

Nanomedicine is an interdisciplinary field of research at the interface of science, engineering, and medicine, with broad clinical applications ranging from molecular imaging to medical diagnostics, targeted therapy, and imageguided surgery. Despite major advances during the past 20 years, there are still major fundamental and technical barriers that need to be understood and overcome. In particular, the complex behaviors of nanoparticles under physiological conditions are poorly understood, and detailed kinetic and thermodynamic principles are still not available to guide the rational design and development of nanoparticle agents. Here we discuss the interactions of nanoparticles with proteins, cells, tissues, and organs from a quantitative physical chemistry point of view. We also discuss insights and strategies on how to minimize nonspecific protein binding, how to design multistage and activatable nanostructures for improved drug delivery, and how to use the enhanced permeability and retention effect to deliver imaging agents for image-guided cancer surgery. © 2015 by Annual Reviews. All rights reserved.

Rahmani A.,University of British Columbia | Zhu X.,University of British Columbia | Zhu X.,Nanjing University | Franz M.,University of British Columbia | Affleck I.,University of British Columbia
Physical Review Letters | Year: 2015

We show that a strongly interacting chain of Majorana zero modes exhibits a supersymmetric quantum critical point corresponding to the c=710 tricritical Ising model, which separates a critical phase in the Ising universality class from a supersymmetric massive phase. We verify our predictions with numerical density-matrix-renormalization-group computations and determine the consequences for tunneling experiments. © 2015 American Physical Society. © 2015 American Physical Society.

Let F:X × ℤ+ → GL(n, ℝ) be a Hölder-continuous linear cocycle whose driving semiflow f:X × ℤ+ → X preserves a probability μ on a compact metric space X. Using the concept of two-sided quasi-Pesin orbits introduced in this paper, we show that the Lyapunov characteristic spectrum of μ can be approached arbitrarily by that of periodic points of f. So, if all periodic points of f have only positive Lyapunov exponents and such exponents are uniformly bounded away from zero, then μ also has only positive exponents. In our arguments, the exponential closing property of the driving semiflow is a basic condition, and it is easy to check that every C1-expanding map of a closed manifold obeys this closing property. Consequently, if f is a C 1+Hölder local diffeomorphism of a closed manifold and if it is Hölder conjugated to some C1-expanding map, then f is itself expanding. This gives a positive answer to a question suggested by Anatole Katok. © 2010 IOP Publishing Ltd and London Mathematical Society.

Wang L.L.,Nanjing University
Zhongguo zhen jiu = Chinese acupuncture & moxibustion | Year: 2011

Through the analysis on warming stimulation at moxa sites and the inflammatory purulent phenomenon by moxibustion, the author points out that moxibustion promotes qi and blood circulation is it's effective feature. It is viewed that "warming and dredging" is the high summarization of moxibustion effect. Moxibustion acts on expelling cold, promoting the circulation in meridian and collateral, clearing away heat, detoxification, strengthening the antipathogenic qi, preventing from diseases and healthcare, etc. All of these functions depend on the effect of moxibustion for circulating qi and blood flow. Hence, "warming and dredging" is the nature of moxibustion.

Wen H.-H.,Nanjing University
Reports on Progress in Physics | Year: 2012

Since the discovery of high temperature superconductivity in iron pnictides in early 2008, many iron-based superconductors with different structures have been discovered, with the highest transition temperature to date being 57K. By the end of 2010, another kind of new superconductor, the Fe-based chalcogenide K 1-xFe 2-ySe 2 was discovered. A naive counting of the electrons in the system would lead to the conclusion that the system is heavily electron overdoped (0.4 e/Fe). Band structure calculations further support this speculation and predict that the hole pockets which are found in the iron pnictides may be missing. This greatly challenges the widely perceived picture that the superconducting pairing is established by exchanging antiferromagnetic (AF) spin fluctuations and that the electrons are scattered between the electron and hole pockets. Later, it was found that both potassium and iron might be deficient in K 1-xFe 2-ySe 2, yielding to a picture of phase separation. In this picture the superconducting phase and the AF phase may separate spatially into different regions. This generates further curiosity about what the real superconducting phase is, what the relationship is between the superconducting phase and the AF phase, and what the parent state is for the superconducting phase. We propose a spider web model for the phase separation, which can explain both the transport and magnetic data. In this paper, we review the status of research in this rapidly growing field and list the important and unresolved issues as perspectives for future research. © 2012 IOP Publishing Ltd.

Yu H.,Japan National Institute of Advanced Industrial Science and Technology | Zhou H.,Japan National Institute of Advanced Industrial Science and Technology | Zhou H.,Nanjing University
Journal of Physical Chemistry Letters | Year: 2013

Lithium-rich layered oxide materials xLi2MnO3· (1-x)LiMO2 (M = Mn, Ni, Co, Fe, Cr, etc.) have attracted much attention for the use of cathode materials in lithium-ion batteries in recent years. However, there are many issues still unclear (the structure and reaction mechanism are ambiguous until now), and numerous scientific challenges (low initial Coulombic efficiency, poor rate capability, and voltage degradation during cycling) of these materials that must be overcome to realize their utilization in commercial lithium-ion batteries. This Perspective focuses on the challenges and prospects associated with the current researching results of these lithium-rich layered cathode materials. Specifically, their average/local structures, reaction mechanisms, and electrochemical properties are discussed. © 2013 American Chemical Society.

Song Z.,Japan National Institute of Advanced Industrial Science and Technology | Zhou H.,Japan National Institute of Advanced Industrial Science and Technology | Zhou H.,Nanjing University
Energy and Environmental Science | Year: 2013

As an alternative to conventional inorganic intercalation electrode materials, organic electrode materials are promising candidates for the next generation of sustainable and versatile energy storage devices. In this paper we provide an overview of organic electrode materials, including their fundamental knowledge, development history and perspective applications. Based on different organics including n-type, p-type and bipolar, we firstly analyzed their working principles, reaction mechanisms, electrochemical performances, advantages and challenges. To understand the development history and trends in organic electrode materials, we elaborate in detail various organics with different structures, including conducting polymers, organodisulfides, thioethers, nitroxyl radical polymers and conjugated carbonyl compounds. The high electrochemical performance, in addition with the unique features of organics such as flexibility, processability and structure diversity, provide them great perspective in various energy storage devices, including rechargeable Li/Na batteries, supercapacitors, thin film batteries, aqueous rechargeable batteries, redox flow batteries and even all-organic batteries. It is expected that organic electrode materials will show their talents in the "post Li-ion battery" era, towards cheap, green, sustainable and versatile energy storage devices. © 2013 The Royal Society of Chemistry.

Zhang K.-J.,Nanjing University | Zhang Y.-X.,University of Chinese Academy of Sciences | Tang X.-C.,University of Chinese Academy of Sciences | Xia B.,Sun Yat Sen University
Earth-Science Reviews | Year: 2012

The elevation of the Tibetan plateau is a revolutionary event in the Earth history, which resulted in change not only of Cenozoic regional and global climate but also of monsoon intensity. A critical aspect for the development of the Tibetan plateau that remains open to intense debate is whether the collision among the Tibetan continental blocks or the subduction of the Tethys prior to the Indo-Asian collision in the Cenozoic contributed to the plateau growth. We propose here that an Andean-type orogen could have been present in southern Tibet from the Jurassic to Early Cretaceous, but collapsed during the Middle Cretaceous, based on a synthesis of existing structural, sedimentary, geochronological, and geochemical data. The orogeny is marked by north-verging Jurassic-Early Cretaceous thrusting in the Lhasa block, a result of flat subduction of the Yarlung-Zangpo Neo-tethys that is recorded by a narrow belt of 205-174. Ma adakitic rocks along the southernmost margin of the Lhasa block. Denudation of the orogen produced a thick (up to 15. km) sequence of Jurassic turbidites and molasse-type sediments on the northern Lhasa block. Widespread Middle Cretaceous (135-100. Ma) postorogenic, strongly peraluminous to calc-alkaline, magmatism and extensional deformation in the Lhasa block and an extensive marine transgression in Tibet indicate that the orogen broke down due to extension resulting from lithosphere delamination and asthenosphere upwelling. Meanwhile, the north-dipping subduction of the Bangong Meso-tethys produced a wide Jurassic-Middle Cretaceous magmatic arc along the southern margin of the Qiangtang block. Findings of 132-108. Ma-aged ophiolites rich with Middle Cretaceous radiolarians in central Tibet indicate that the Bangong Meso-tethys did not close until the Late Cretaceous. Repeated flat slab subduction of the Yarlung-Zangpo Neo-tethys occurred during the Late Cretaceous (90-78. Ma) as indicated by the adakites in the southernmost Lhasa block, which, together with the ongoing Qiangtang-Lhasa collision, could have contributed to the growth of the Tibetan plateau. © 2012 Elsevier B.V.

Yin Y.,Nanjing University | Zhang C.,Shanghai JiaoTong University
Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms | Year: 2013

We show for a broad class of counting problems, correlation decay (strong spatial mixing) implies FPTAS on planar graphs. The framework for the counting problems considered by us is the Holant problems with arbitrary constant-size domain and symmetric constraint functions. We define a notion of regularity on the constraint functions, which covers a wide range of natural and important counting problems, including all multi-state spin systems, counting graph homomorphisms, counting weighted matchings or perfect matchings, and all counting CSPs and Holant problems with symmetric constraint functions of constant arity. The core of our algorithm is a fixed-parameter tractable algorithm which computes the exact values of the Holant problems with regular constraint functions on graphs of bounded treewidth. By utilizing the locally tree-like property of apex-minor-free families of graphs, the parameterized exact algorithm implies an FPTAS for the Holant problem on these graph families whenever the Gibbs measure defined by the problem exhibits strong spatial mixing. We further extend the recursive coupling technique to establish the strong spatial mixing on Holant problems. As consequences, we have new deterministic approximation algorithms on planar graphs for several counting problems. Copyright © SIAM.

Feng L.,University of Stuttgart | Li H.,Nanjing University
Journal of Urban Planning and Development | Year: 2012

Over the past 30 years, land development and consumption have been out of control and have kept expanding blindly, especially to marginal areas of some metropolises in China. The conflict caused by urban sprawl among socioeconomic development, resources, ecology, and the environment is becoming more and more severe. This study's primary objective is to recognize the spatial patterns of urban sprawl. Taking Jiangning District as a research area, the built-up areas of fourdifferent years (1979, 1988, 1997, and 2003) were extracted from classified images using Landsat MSS/TM images. These, together with landscape metrics such as contagion index, fractal-dimension index, and shape index where used to recognizethe spatial patterns of sprawl in Jiangning. From classified images, rapid urban expansion with low density towards the urban fringe has been observed. The sprawling area in the north part is more severe, and sprawling areas also include the marginal area of the nearby suburbs. These findings were tested through landscape metrics, which was necessary to quantify the spatial patterns of urban sprawl. This study demonstrates that timely and accurate monitoring is very importantfor understanding the relationships and interactions between human and natural phenomena, and that it can promote efficiency. Additionally, combining remote sensing with landscape metrics is an effective way to determine the spatial patterns of urban sprawl. © 2012 American Society of Civil Engineers.

Urbanization has accelerated in China, and a large amount of arable land has been transformed into urban land. Moreover, the number of landless peasants has continually increased. Peasants lose not only their land, but also a series of rights and interests related with land. The problems of landless peasants have been long-standing; however, only a few studies have examined their health or quality of life (QOL). This paper assesses the QOL of landless peasants in the Yangtze River Delta (YRD) region, analyzes gender differences, and explores health inequity. Data are derived from household samples in six resettlement residential areas of three cities (Nanjing, Hangzhou, and Yangzhou) in the YRD region (N = 1,500; the effective rate = 82.4%). This study uses the short version of World Health Organization Quality of Life questionnaire (WHOQOL-BREF) scale to measure the QOL of landless peasants, and performs confirmatory factor analysis (CFA) and analyze gender differences in QOL on the basis of CFA. First, we use Analysis of Variance and Non-parametric Tests to test if the differences of mean value of testing generals have statistical significances. Results shows significant differences occur between the impacts of different genders on the four domains of QOL (physical health, psychological health, social relationships, and environment). The internal reliability of the WHOQOL-BREF scale is good (Cronbach's alpha > 0.8), and the four domains of QOL are connected with each other. Second, scores in each QOL domain are commonly low, whereas the scores of females are much lower, indicating a poorer QOL than that of males. Third, results of the CFA of the QOL domains and their related observed variables indicate a good model fit. Fourth, results imply that the order of importance of the four domains (psychological health (males = 26.74%, females = 27.17%); social relationships (males = 26.23%, females = 25.35%); environment (males = 25.70%, females = 24.40%); and physical health (males = 21.33%, females = 23.08%)) affecting QOL from high to low is the same for landless male and female peasants, whereas the proportion of importance is different between genders. The results highlight the importance of government intervention to improve the QOL of Chinese landless peasants, ultimately reducing health inequity.

Li W.,Nanjing University
IEEE Transactions on Cybernetics | Year: 2016

In this paper, we first formulate the confinement-escape problem of a defender and an evader who attempts escaping from a circular region, which differs from the traditional pursuit-evasion problems. In our setting of the confinement-escape problem, the defender is restricted to move and patrol on the circle, trying to prevent possible escape of the evader who is initially located inside the circle. We describe and characterize some general properties of the problem, and then design two bio-inspired control strategies for the evader and the defender, respectively. In addition, we illustrate some possible motion patterns of the system, investigate the escaping time as a function of the relative-initial-positions of the agents, as well as the winning sets of the two players, respectively, under different system-parameters. To that end, we characterize the contour lines of the winning sets with their gradient properties. Finally, we indicate the abrupt phase transitions between successful confinement and escaping, revealing the strong sensitivity and nonlinearities of the system under critical conditions. © 2013 IEEE.

Background: The alarming progression of the aging trend in China attracts much attention in the country and abroad. In 2003, the Chinese central government launched the New Cooperative Medical Scheme (NCMS) to resolve the inequity problem of health in regions with inadequate infrastructure and relative poverty. The rural elderly are the main beneficiaries of this policy; the improvement of their health through the medical insurance policy require exploration. Methods. This study used data obtained from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) conducted in 2005 and 2008. Elderly people living in rural areas and aged 60 and above were screened for the investigation. A total of 8658 and 9904 elderly people were selected from 2005 and 2008, respectively. By establishing models and employing multi-logistic analysis, stereotype logistic analysis, we examined the effect of NCMS organized by Chinese government on three domains of the health of the rural elderly. Results: A total of 948 and 6361 elderly people participated in NCMS in 2005 (n = 8658) and 2008 (n = 9904), respectively. With regard to the independent variables, the number of participants in NCMS increased, whereas province distribution, gender, and years of education only slightly changed. As for the dependent variables, the rural elderly in 2005 had poor general health but good psychological health. Differences were found between different moods. Old people who engage in much outdoor activity can take care of themselves. After three-year promotion of NCMS, the differences between 2005 and 2008 indicate that the physical function of the rural elderly worsen, whereas the general health and psychological health improves. Conclusions: (1) In the 2005 data and 2008 data, result shows that NCMS participation can promote the self-rated quality and health change of the elderly. (2) After three years, the alleviation effect on anxiety and loneliness changed from insignificant to significant. Participants in NCMS have a stronger sense of uselessness, which weakens with time. (3)NCMS participation passes the significance test in "outdoor activities" and "pick a book up from the floor" model. Elderly participants indicated higher frequencies of outdoor activities. © 2014Liang and Lu; licensee BioMed Central Ltd.

Wang H.,Nanjing University | Wang H.,University of Illinois at Urbana - Champaign
Current Organic Chemistry | Year: 2014

In this review, we discuss the advances in understanding the reactivity of quinone methide (QM) intermediates and the reversibility of DNA alkylation by QMs in the past two decades. QMs react with strong nucleophiles of DNA under kinetic control but reversibly. The effective lifetime of QMs can be extended through repeated capture and release from DNA adducts. A QM-acridine conjugate DNA cross-linking agent remains dynamic and "migrates" among DNA strands through multiple strand exchange reactions until forming stable adducts irreversibly. Self-adducts of QM-biopolymer conjugates exhibit strong capability to alkylate complementary DNA strands in a sequence specific manner. © 2014 Bentham Science Publishers.

Qian Z.,Nanjing University
Inverse Problems in Science and Engineering | Year: 2010

We consider the determination of the boundary temperature from one measured transient data temperature at some interior point of a one-dimensional semi-infinite conductor. Mathematically, it can be formulated as a fractional-diffusion inverse heat conduction problem where data are given at x = l and we want to determine a solution for 0

Li J.,Xuzhou Medical College | Zhu J.-J.,Nanjing University | Xu K.,Xuzhou Medical College
TrAC - Trends in Analytical Chemistry | Year: 2014

Fluorescent metal nanoclusters (NCs) are a class of emerging fluorescent materials. They have excellent photostability and biocompatibility with sub-nanometer size and are easy to synthesize. Taking advantage of these features, fluorescent metal NCs have been involved in exciting developments of analytical methods for fluorescent biosensing and bioimaging. In this review, we first summarize the approaches to synthesis and bioconjugation for fluorescent metal NCs (Ag, Au, Cu and Pt). We then highlight their applications as fluorescent probes for metal ions, small molecules, nucleic acids, and protein detection. We also summarize the use of metal NCs in cellular and in-vivo targeting and imaging. Finally, we envision the various prospects for research on fluorescent metal NCs in the future. © 2014 Elsevier Ltd.

Zhang M.-L.,Nanjing Southeast University | Zhou Z.-H.,Nanjing University
IEEE Transactions on Knowledge and Data Engineering | Year: 2014

Multi-label learning studies the problem where each example is represented by a single instance while associated with a set of labels simultaneously. During the past decade, significant amount of progresses have been made toward this emerging machine learning paradigm. This paper aims to provide a timely review on this area with emphasis on state-of-the-art multi-label learning algorithms. Firstly, fundamentals on multi-label learning including formal definition and evaluation metrics are given. Secondly and primarily, eight representative multi-label learning algorithms are scrutinized under common notations with relevant analyses and discussions. Thirdly, several related learning settings are briefly summarized. As a conclusion, online resources and open research problems on multi-label learning are outlined for reference purposes. © 1989-2012 IEEE.

Qu Y.,Nanjing University | Cheng G.,Nanjing Southeast University
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2011

Web ontologies provide shared concepts for describing domain entities and thus enable semantic interoperability between applications. To facilitate concept sharing and ontology reusing, we developed Falcons Concept Search, a novel keyword-based ontology search engine. In this paper, we illustrate how the proposed mode of interaction helps users quickly find ontologies that satisfy their needs and present several supportive techniques including a new method of constructing virtual documents of concepts for keyword search, a popularity-based scheme to rank concepts and ontologies, and a way to generate query-relevant structured snippets. We also report the results of a usability evaluation as well as user feedback. © 2011 IEEE.

Wu J.,Yunnan University | Zhang L.,Yunnan University | Tang J.,Nanjing University
Atmospheric Environment | Year: 2012

The visibility on sunny days in 543 stations of China were analyzed, the results shows: The annual mean visibility on sunny days is higher in Northwest China and lower in Southeast China, which is similar to the distribution of aerosol optical depth. Visibility in summer is lower than in winter in southeast China, which relates to the stronger solar radiation in summer benefits to aerosol formation; Visibility in large cities is lower than small cities, and visibility of large and medium cities in summer is lower than winter but for small cities is opposite; The visibility decrease trend is revealed for most stations in recent 50 years, and the maximum trend coefficient -0.8 is found in delta regions of Pearl River and Yangtze River with climatic trend of -10. km/10a. The obvious visibility decrease for large and medium cities was from 1960s' to 1990s' accompanied by a slow increase later, and it was after the middle of 1990s' visibility began to decrease for small cities; The diffuse radiation on sunny days show increase trend in recent 50 years, and it significantly correlates to visibility on sunny days with a correlation coefficient of -0.59 passing . t-test at 0.001 significance level; Visibility on sunny days also correlates to total fuel consumption data and number of vehicles in China. Aerosol pollution should account for the obvious decrease of sunny visibility. © 2012 Elsevier Ltd.

Zhou Z.-H.,Nanjing University
Zidonghua Xuebao/Acta Automatica Sinica | Year: 2013

Traditional supervised learning generally requires a large amount of labeled data as training examples; in many real tasks, however, although it is usually easy to acquire a lot of data, it is often expensive to get the label information. Can we improve the learning performance with limited amount of labeled data by exploiting the large amount of unlabeled data? For this purpose, semi-supervised learning has become a hot topic of machine learning during the past ten years. One of the mainstream paradigms, the disagreement-based semi-supervised learning, trains multiple learners to exploit the unlabeled data, where the "disagreement" among the learners is crucial. This article briefly surveys some research advances of this paradigm. Copyright © 2013 Acta Automatica Sinica. All rights reserved.

Sun Z.-W.,Nanjing University
Finite Fields and their Applications | Year: 2013

In this paper we deduce some new supercongruences modulo powers of a prime p>3. Let d∈{0,1,.,(p-1)/2}. We show thatΣk=0(p-1)/2(2kk)(2kk+d) 8k≡0(modp)ifd≡p+12(mod2), andΣk=0(p-1)/2(2kk) (2kk+d)16k≡(-1p)+p2(-1)d4Ep- 3(d+12)(modp3), where Ep-3(x) denotes the Euler polynomial of degree p-3, and (-) stands for the Legendre symbol. The paper also contains some other results such asΣk=0p-1k( 1+(-1p))/2(6k3k)(3kk)864k≡0(modp2). © 2013 Elsevier Inc.

Chen Z.-X.,Nanjing University | Xiao H.-M.,Nanjing University of Science and Technology
Propellants, Explosives, Pyrotechnics | Year: 2014

Energetic materials are a special and important kind of substance. Impact sensitivity, which refers to the vulnerability to explosion under external stimuli, measures the safety and reliability of an energetic material and is a critical property. Various efforts have been made to rationalize the impact sensitivity of different types of energetic materials. Since a chemical explosion is a chemical reaction dominated phenomenon, a comprehensive understanding of such explosive processes requires detailed information of chemical bonding and molecular interaction. Quantum chemistry provides a modern theory of chemical bonding and computational quantum chemistry is a powerful tool to investigate chemical phenomena. Even at the very beginning of computational quantum chemistry, researchers in the field of energetic materials have begun to apply quantum chemistry to explosive properties. In this paper we review the quantum chemistry studies on impact sensitivity and examine various quantum chemistry derived parameters used to rationalize the impact sensitivity ordering of various energetic materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

He M.,Nanjing University | Zheng H.,Nanjing Normal University | Bookhagen B.,University of California at Santa Barbara | Clift P.D.,Louisiana State University
Earth-Science Reviews | Year: 2014

The Yangtze River dominates the drainage of eastern Asia, yet the processes that control erosion within the basin are obscure, making the interpretation of the detritus record difficult. In this study we used U-Pb dating of zircon grains from the modern main stream and major tributaries to identify the sources of sediment production, based on the diversity of zircon ages associated with the different tectonic blocks over which the Yangtze flows. We demonstrate that tributaries in the central part of the catchment are the most important in supplying sand-sized sediment to the main stream, i.e., the Hanjiang, Xiangjiang and Jialingjiang, as well as along the main stream (Jinshajiang) between Panzhihua and Yibin. Surprisingly, the rivers draining the eastern edge of the Tibetan plateau do not appear to dominate the modern budget, despite their tectonic activity and steep topography. Sediment-productive drainages have high specific stream power (because of significant rainfall as well as steep topography), but are also the locations of early human settlement and agriculture. We suggest that it is the combination of high specific stream power and anthropogenic disruption to the landscape that facilitates sediment supply to the main stream. Because of zircon transport times spanning thousands of years reworking during early to late Neolithic settlement, may be more important than recent farming in controlling the zircon population of the river sands. Our sediment-transport framework explains the discrepancy between sediment sources identified by zircon dating and the strong sediment production in the upper reaches favored by studies of fine-grained sediment or cosmogenic isotopes applied to quartz grains. © 2014 Elsevier B.V.

Zheng G.,Nanjing University | Moskal L.M.,University of Washington
International Journal of Applied Earth Observation and Geoinformation | Year: 2012

Forest stand point clouds generated from multiple scan locations using terrestrial laser scanning (TLS) have diverse range of spatial distribution patterns. These in turn have an effect on the direct leaf area index (LAI) estimation from the point cloud. However, the most effective placement of the scanning equipment in homogeneous vs. heterogeneous stands has not been investigated. In this research, TLS was used to sample an evenly planted Douglas-fir (Pseudotsuga menziesii) seedling forest stand and a mature heterogeneous forest stand dominated by Douglas-fir (P. menziesii) and Western hemlock (Tsuga heterophylla). A new method, circular point cloud slicing, was developed to explore the spatial variation of point density for both azimuthal angular and radial directions. The results show that alone, a central location 360{ring operator} scan data, does not capture all of the stand characteristics and less than 50% of variation of the estimation of effective leaf area index (LAIe) of a mature heterogeneous stand. Thus, reducing occlusion, by incorporating additional lateral side view scans, is necessary to comprehensively represent the canopy structure, and structural variation of the heterogeneous forest stand. It was also shown, based on the assumption that the comprehensive scan combination can fully represent the forest stand, and that LAIe estimated from the comprehensive multi-direction mosaiced dataset are higher by twofold compared to the result from central scan only. © 2012 Elsevier B.V.

Miao B.F.,Johns Hopkins University | Miao B.F.,Nanjing University | Huang S.Y.,Johns Hopkins University | Qu D.,Johns Hopkins University | Chien C.L.,Johns Hopkins University
Physical Review Letters | Year: 2013

The inverse spin Hall effect (ISHE) has been observed only in nonmagnetic metals, such as Pt and Au, with a strong spin-orbit coupling. We report the observation of ISHE in a ferromagnetic permalloy (Py) on ferromagnetic insulator yttrium iron garnet (YIG). Through controlling the spin current injection by altering the Py-YIG interface, we have isolated the spin current contribution and demonstrated the ISHE in a ferromagnetic metal, the reciprocal phenomenon of the anomalous Hall effect. A large spin Hall angle in Py, determined from Py thin films of different thicknesses, indicates many other ferromagnetic metals may be exploited as superior pure spin current detectors and for applications in spin current. © 2013 American Physical Society.

Zhao B.,Nanjing University | Chen Y.-W.,National Central University
Journal of Physics and Chemistry of Solids | Year: 2011

Ag/TiO2 sol with narrow particle size distribution was synthesized using TiCl4 as the starting material. TiCl4 was converted to Ti(OH)4 gel. The Ag/TiO2 sol was prepared by a process where H2O2 was added and then heated at 9097 °C. After condensation reaction and crystallization, a transparent sol with suspended Ag/TiO2 was formed. Ag/TiO2 was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, contact angle analysis, and X-ray photoelectron spectroscopy. The photocatalytic properties of Ag/TiO2 film were evaluated by degradation of methylene blue in aqueous solution under UV light irradiation. The suspended Ag/TiO2 particles were rhombus primary particles with the major axis ca. 40 nm and the minor axis ca. 10 nm. Ag nanoparticles were well dispersed on TiO2 and the particle size was only 12 nm. Ag could restrain the recombination of photo-generated electrons and holes effectively. Transparent thin films could be obtained through dip-coating glass substrate in the sol. The thin film had strong hydrophilicity after being illuminated by UV light. Ag/TiO2 film showed a significant increase in photocatalytic activity compared to the TiO2 film. The high amount of surface hydroxyls on Ag/TiO2 film also played an important role in its photocatalytic activity. © 2011 Elsevier Ltd. All rights reserved.

Wu Q.,Nanjing University | Zhang X.,University of Alaska Fairbanks
Journal of Geophysical Research: Atmospheres | Year: 2010

A lagged maximum covariance analysis is applied to investigate linear covariability between monthly sea ice concentration (SIC) and atmosphere circulation in the Northern Hemisphere. The dominant signal is the atmospheric forcing of SIC anomalies throughout the year, but a wintertime atmospheric signal resembling the negatively polarized Arctic Oscillation/North Atlantic Oscillation is significantly correlated with persistently reduced SIC anomalies in the North Atlantic and Pacific sides of Arctic Shelf seas up to the preceding summer. The leading time of SIC anomalies provides an implication for skillful predictability of wintertime atmospheric variability. Copyright 2010 by the American Geophysical Union.

Zhang Q.,Harvard - Smithsonian Center for Astrophysics | Wang K.,European Southern Observatory | Lu X.,Harvard - Smithsonian Center for Astrophysics | Lu X.,Nanjing University | Jimenez-Serra I.,European Southern Observatory
Astrophysical Journal | Year: 2015

Sufficiently massive clumps of molecular gas collapse under self-gravity and fragment to spawn a cluster of stars that have a range of masses. We investigate observationally the early stages of formation of a stellar cluster in a massive filamentary infrared dark cloud, G28.34+0.06 P1, in the 1.3 mm continuum and spectral line emission using the Atacama Large Millimeter/Submillimeter Array. Sensitive continuum data reveal further fragmentation in five dusty cores at a resolution of several 103 AU. Spectral line emission from C18O, CH3OH, 13CS, H2CO, and N2D+ is detected for the first time toward these dense cores. We found that three cores are chemically more evolved as compared with the other two; interestingly, though, all of them are associated with collimated outflows as suggested by evidence from the CO, SiO, CH3OH, H2CO, and SO emission. The parsec-scale kinematics in exhibit velocity gradients along the filament, consistent with accretion flows toward the clumps and cores. The moderate luminosity and the chemical signatures indicate that the five cores harbor low- to intermediate-mass protostars that likely become massive ones at the end of the accretion. Despite the fact that the mass limit reached by the 1σ dust continuum sensitivity is 30 times lower than the thermal Jeans mass, there is a lack of a distributed low-mass protostellar population in the clump. Our observations indicate that in a protocluster, low-mass stars form at a later stage after the birth of more massive protostars. © 2015. The American Astronomical Society. All rights reserved.

Jiang L.H.,Nanjing University
Zhen ci yan jiu = Acupuncture research / [Zhongguo yi xue ke xue yuan Yi xue qing bao yan jiu suo bian ji] | Year: 2010

OBJECTIVE: To observe the effect of electroacupuncture (EA) on the profiles of hippocampal whole-genome expression in depression rats so as to study its underlying mechanism in relieving depression. METHODS: Thirty male SD rats were randomized into normal, model and EA groups (n = 10/group). Depression model was established by chronic unpredictable stress stimulation (forced ice-water swimming, electric shock, tail-clamping, etc.) and lonely raising for 21 days. EA (2 Hz, 1 mA) was applied to "Baihui"(GV 20) and "Yintang" (EX-HN 3) for 15 min, once daily for 7 days. The rats' ethological activities (horizontal and vertical movements) were detected with Open-field test in Morris labyrinth, and 1% sucrose solution consumption was detected. After termination of the treatment, the rats were killed and their hippocampal tissues were taken out for analyzing the whole-genome expression with Roche-NimbleGen chips (Rattus norvegicus 12 x 135 Karray). RESULTS: Compared with normal group, the distance of horizontal movement, rearing times, and sucrose consumption at day 21 and day 28 of model group decreased considerably (P < 0.01). In comparison with model group, the sucrose consumption at day 28 in EA group increased significantly (P < 0.05). Results of gene expression microarray displayed that compared with normal group, of the down-regulated and up-regulated genes due to modeling, 101 and 125 turned to normal in their expression, respectively following EA treatment. The down-regulated genes involve energy and substance metabolism, protein biosynthesis, etc., and the up-regulated genes involve blood clotting, immunity, inflammation, apoptosis, etc. CONCLUSION: EA of GV 20 and EX-HN 3 can normalize chronic stress stimulation induced down- and up-regulated expression of many genes in depression rats, which may contribute to its clinical effect in relieving depression.

Ding Y.,East China University of Science and Technology | Ding Y.,Nanjing University | Tang Y.,East China University of Science and Technology | Zhu W.,East China University of Science and Technology | Xie Y.,East China University of Science and Technology
Chemical Society Reviews | Year: 2015

Metal ions and anions play important roles in many industrial and biochemical processes, and thus it is highly desired to detect them in the relevant systems. Small organic molecule based sensors for selective and sensitive detection of target ions show the advantages of low cost, high sensitivity and convenient implementation. In this area, pyrrole has incomparable advantages. It can be easily incorporated into linear and macrocyclic conjugated structures such as dipyrrins, porphyrins, and N-confused porphyrins, which may utilize the imino N and amino NH moieties for binding metal ions and anions, respectively. In this tutorial review, we focus on representative examples to describe the design, syntheses, sensing mechanisms, and applications of the conjugated oligopyrroles. These compounds could be used as colorimetric or fluorescent ion probes, with the advantages of vivid colour and fluorescence changes, easy structural modification and functionalization, and tunable emission wavelengths. Compared with normal porphyrins, simple di- and tripyrrins, as well as some porphyrinoids are more suitable for designing fluorescence "turn-on" metal probes, because they may exhibit flexible confirmations, and metal coordination will improve the rigidity, resulting in vivid fluorescence enhancement. It is noteworthy that the oligopyrrolic moieties may simultaneously act as the binding unit as well as the reporting moiety, which simplifies the design and syntheses of the probes. This journal is © The Royal Society of Chemistry.

Yan L.,Nanjing University
Journal of inorganic biochemistry | Year: 2012

Palladium(II) complexes are potential antitumor metallodrugs for their chemical resemblance to platinum(II) complexes. Two palladium(II) complexes (1 and 2) in the formula of [PdL(n)Cl] [L(1) = N-(tert-butoxycarbonyl)-l-methionine-N'-8-quinolylamide, L(2) = L-alanine-N'-8-quinolylamide] have been synthesized accordingly. The structures of the complexes were fully characterized by X-ray crystallography. The palladium(II) center in 1 is coordinated by two N atoms and an S atom from L(1) with one chloride anion as the leaving group; while that in 2 is coordinated by three N atoms from L(2) with one chloride anion as the leaving group. The interaction between complex 1 and human serum albumin (HSA) has been investigated using fluorescence and circular dichroism spectroscopies. The complex seems to react with HSA chiefly through hydrophobic and electrostatic interactions, and it does not alter the α-helical nature of HSA. The cytotoxicity of these complexes has been tested against the human cervical cancer (HeLa), human mammary cancer (MCF-7), and human lung cancer (A-549) cell lines. Complex 1 displays a cytotoxic activity comparable to that of cisplatin, but complex 2 is less active than cisplatin. Copyright © 2011 Elsevier Inc. All rights reserved.

Zhu J.,Nanjing University of Aeronautics and Astronautics | Qiu J.,Nanjing University
Journal of Computational Physics | Year: 2011

The local discontinuous Galerkin (LDG) method is a spatial discretization procedure for convection-diffusion equations, which employs useful features from high resolution finite volume schemes, such as the exact or approximate Riemann solvers serving as numerical fluxes and limiters, which is termed as Runge-Kutta LDG (RKLDG) when TVD Runge-Kutta method is applied for time discretization. It has the advantage of flexibility in handling complicated geometry, h-p adaptivity, and efficiency of parallel implementation and has been used successfully in many applications. However, the limiters used to control spurious oscillations in the presence of strong shocks are less robust than the strategies of essentially non-oscillatory (ENO) and weighted ENO (WENO) finite volume and finite difference methods. In this paper, we investigated RKLDG methods with WENO and Hermite WENO (HWENO) limiters for solving convection-diffusion equations on unstructured meshes, with the goal of obtaining a robust and high order limiting procedure to simultaneously obtain uniform high order accuracy and sharp, non-oscillatory shock transition. Numerical results are provided to illustrate the behavior of these procedures. © 2010 Elsevier Inc.

Xu C.,Texas A&M University-Commerce | Xu C.,Nanjing University | Li B.-A.,Texas A&M University-Commerce
Physical Review C - Nuclear Physics | Year: 2010

Within the interacting Fermi gas model for isospin asymmetric nuclear matter, effects of the in-medium three-body interaction and the two-body short-range tensor force owing to the ρ meson exchange, as well as the short-range nucleon correlation on the high-density behavior of the nuclear symmetry energy, are demonstrated respectively in a transparent way. Possible physics origins of the extremely uncertain nuclear symmetry energy at suprasaturation densities are discussed. © 2010 The American Physical Society.

Zhang X.-P.,Nanjing University
Journal of the Royal Society, Interface / the Royal Society | Year: 2014

The tumour suppressor p53 is activated to induce cell-cycle arrest or apoptosis in the DNA damage response (DDR). p53 phosphorylation at Ser46 by HIPK2 (homeodomain-interacting protein kinase 2) is a critical event in apoptosis induction. Interestingly, HIPK2 is degraded by Mdm2 (a negative regulator of p53), whereas Mdm2 is downregulated by HIPK2 through several mechanisms. Here, we develop a four-module network model for the p53 pathway to clarify the role of interplay between Mdm2 and HIPK2 in the DDR evoked by ultraviolet radiation. By numerical simulations, we reveal that Mdm2-dependent HIPK2 degradation promotes cell survival after mild DNA damage and that inhibition of HIPK2 degradation is sufficient to trigger apoptosis. In response to severe damage, p53 phosphorylation at Ser46 is promoted by the accumulation of HIPK2 due to downregulation of nuclear Mdm2 in the later phase of the response. Meanwhile, the concentration of p53 switches from moderate to high levels, contributing to apoptosis induction. We show that the presence of three mechanisms for Mdm2 downregulation, i.e. repression of mdm2 expression, inhibition of its nuclear entry and HIPK2-induced degradation, guarantees the apoptosis of irreparably damaged cells. Our results agree well with multiple experimental observations, and testable predictions are also made. This work advances our understanding of the regulation of p53 activity in the DDR and suggests that HIPK2 should be a significant target for cancer therapy. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Shu L.-S.,Nanjing University
Geological Bulletin of China | Year: 2012

Studies suggest that at least four stages of regional-scale tectonic and magmatic events have taken place in the South China block, namely, geodynamic processes of Neoproterozoic and Late Mesozoic active continental margins, Early Paleozoic and Early Mesozoic intracontinental orogenies. The Cathaysia block was a pre-Nanhua basement consisting mainly of Neoproterozoic rocks instead of a stable old land. It experienced a complex evolution from assembly through break-up to re-assembly. The intracontinental shortening during Silurian led to the stabilization of the united South China continent. The entire South China Block was under a shore-shallow sea-slope setting, with no translithospheric fault, no regional-scale volcanism and mantle-derived magmatism in the period from Sinian to Jurassic, during which polyphase tectonic and magmatic events occurred in the united South China lithosphere. It evolved into a part of the Late Mesozoic Western Pacific active continental margin after the Early-Middle Jurassic transformation from Tethysian to Pacific tectonic regimes. The South China lithosphere experienced polyphase continental growth due to the dominant lateral accretion of block assembly accompanied by vertical growth of magma up-swarming. During the Cretaceous, the South China basin and range tectonics occurred in the western shore of the Pacific Ocean due to strong intracontinental extension caused by the northwestward subduction of the Pacific Ocean. Long-term intraplate tectonism and polystage granitic magmatism provided South China with a favorable condition of metallization, forming various large-size ore deposits and resources. Neoproterozoic Nanhua Period and Early Cretaceous were two dominant stages of metallization, with various types of ore deposits being chiefly formed in the Early Cretaceous period.

Zhang S.-P.,Nanjing University of Science and Technology | Song H.-O.,Nanjing University
New Journal of Chemistry | Year: 2012

Supramolecular hybrid materials of graphene oxide (GO) with octadecylamine or dodecylamine have been fabricated by a simple self-assembly technique at room temperature. Many characterization methods have been used to research the micelle-like nanostructures. Compared to unmodified GO, the alkyl-functionalized graphene hybrids could be easily dispersed in various nonpolar organic solvents, such as petroleum ether, n-heptane, isooctane, dimethylbenzene etc., rather than in polar solvents. It was found that alkylamine plays a key role during such preparation. Octadecanol (ODO) produced hardly any modification of GO under the conditions, because the so-called product (GO-ODO) exhibits a high degree of similarity to GO in solvent dispersion behaviour and the Fourier transform infrared spectroscopy. The addition of alkylamine significantly improves the thermal stability of the nanomaterials. The improved thermal degradation temperatures can be obtained for polyethylene glycol and polymethyl methacrylate after filling it with as little as 1 wt% of the hybrid, suggesting their great potential as novel nanofillers in industry. This journal is © 2012 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Luo H.,CAS Institute of Physics | Wen H.-H.,Nanjing University
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

We report the transport results of underdoped Bi2+xSr2-xCuO6+δ (0.05≤x≤0.40) single crystals. A close relationship between the upturn of in-plane resistivity [ρab(T)] and the sign of magnetoresistance in the normal state upon Bi substitutions is found. Combining the results of the field and angular dependence of magnetoresistance, the model fitting of ρab(T), as well as the Hall coefficient results, we suggest a crossover from weak to strong localization of charge carriers in the underdoped Bi2+xSr2-xCuO6+δ, which may be responsible for the rather narrow superconducting dome in this system. © 2014 American Physical Society.

Kang M.,University of Hong Kong | Kang M.,Nankai University | Feng T.,University of Hong Kong | Wang H.-T.,Nankai University | And 2 more authors.
Optics Express | Year: 2012

We propose an ultra-Thin metamaterial constructed by an ensemble of the same type of anisotropic aperture antennas with phase discontinuity for wave front manipulation across the metamaterial. A circularly polarized light is completely converted to the cross-polarized light which can either be bent or focused tightly near the diffraction limit. It depends on a precise control of the optical-Axis profile of the antennas on a subwavelength scale, in which the rotation angle of the optical axis has a simple linear relationship to the phase discontinuity. Such an approach enables effective wave front engineering within a subwavelength scale. © 2012 Optical Society of America.

Study Design. Descriptive study, stratified sampling. Objective. Using dynamic computed tomographic perfusion (CTP) to explore the age-related distribution patterns of the microcirculation perfusion in the vertebral marrow, the vertebral bone mineral density (BMD), and the intervertebral discal degeneration (IDD) further to discuss the possible causation between them. Summary of Background Data. A latest viewpoint deemed that reduced blood supply of the vertebral marrow was correlated with an increased incidence of IDD and loss of BMD. However, the causative relationship between them needs more investigation. Methods. One hundred eighty-six general people were randomly enrolled by stratified sampling and grouped by age: 15 years or less, 16 to 25 years, 26 to 35 years, 36 to 45 years, 46 to 55 years, 56 to 65 years, 66 to 75 years, and 76 years or more. Both CTP and BMD of the third and fourth lumbar vertebral marrow were measured, and the IDD incidence of the third-fourth vertebrae was assessed. The temporal-spatial distribution patterns of the age-related changes of CTP, BMD, and IDD were described, and the correlations between them were calculated. Results. Microcirculatory perfusion of the vertebral marrow developed to maturate by 25 years, maintained stable at 35 years, and then declined by age after 35 years. BMD grew to a peak phase in 26 to 45 years and then dropped by years. However, IDD presented a sudden increase after 45 years of age. CTP (blood flow [r = 0.806], blood volume [r = 0.685], and permeability [r = 0.619]) showed strong positive correlations and CTP (time to peak [r = - 0.211], mean transit time [r = - 0.598]) showed negative correlations with BMD. Meanwhile, CTP (blood flow [r = - 0.815], blood volume [r = - 0.753], and permeability [r = - 0.690]) had strong negative correlations and CTP (time to peak [r = 0.323] and mean transit time [r = 0.628]) had positive correlations with the incidence of IDD. Conclusion. Aging-related decrease of the microcirculatory perfusion of the lumbar vertebral marrow preceded the loss of BMD and the onset of IDD, indicating their possible causal relationship. Copyright © 2015 Wolters Kluwer Health, Inc.

Wu W.,Nanjing University
Science of the Total Environment | Year: 2016

The geographic region around the northern and northeastern Tibetan Plateau is the source of several inland rivers (e.g. Tarim River) of worldwide importance that are generated in the surrounding mountains systems of Tianshan, Pamir, Karakorum, and Qilian. To characterize chemical weathering and atmospheric CO2 consumption in these regions, water samples from the Tarim, Yili, Heihe, Shule, and Shiyang Rivers were collected and analyzed for major ion concentrations. The hydrochemical characteristics of these inland rivers pronouncedly distinguish them from large exorheic rivers (e.g., the Yangtze River and the Yellow River), as reflected in very high total dissolution solids (TDS) values. TDS was 115-4345mgl-1 with an average of 732mgl-1, which is an order of magnitude higher than the mean value for world rivers (65mgl-1). The Cheerchen River, Niya River, Keliya River and the terminal lakes of the Tarim River and the Heihe River have TDS values higher than 1gl-1, indicating saline water that cannot be directly consumed. Therefore, the problem of sufficient and safe drinking water has become increasingly prominent in the northwestern China arid zone. According to an inversion model, the contribution from evaporite dissolution to the dissolved loads in these rivers is 12.5%-99% with an average of 54%. The calculated silicate and carbonate weathering rates are 0.02-4.62tkm-2y-1 and 0.01-11.7tkm-2y-1 for these rivers. To reduce the influence of lithology, only the silicate weathering rates in different parts of the Tibetan Plateau are compared. A rough variation tendency can be seen in the rates: northern regional (0.15-1.73tkm-2y-1)

Tian W.-D.,Soochow University of China | Ma Y.-Q.,Soochow University of China | Ma Y.-Q.,Nanjing University
Chemical Society Reviews | Year: 2013

It is a great challenge for nanomedicine to develop novel dendrimers with maximum therapeutic potential and minimum side-effects for drug and gene delivery. As delivery vectors, dendrimers must overcome lots of barriers before delivering the bio-agents to the target in the cell. Extensive experimental investigations have been carried out to elucidate the physical and chemical properties of dendrimers and explore their behaviors when interacting with biomolecules, such as gene materials, proteins, and lipid membranes. As a supplement of the experimental techniques, it has been proved that computer simulations could facilitate the progress in understanding the delivery process of bioactive molecules. The structures of dendrimers in dilute solutions have been intensively investigated by monomer-resolved simulations, coarse-grained simulations, and atom-resolved simulations. Atomistic simulations have manifested that the hydrophobic interactions, hydrogen-bond interactions, and electrostatic attraction play critical roles in the formation of dendrimer-drug complexes. Multiscale simulations and statistical field theories have uncovered some physical mechanisms involved in the dendrimer-based gene delivery systems. This review will focus on the current status and perspective of theoretical and computational contributions in this field in recent years. (275 references) © The Royal Society of Chemistry 2013.

Chen G.-Y.,Nankai University | Song F.,Nankai University | Wang H.-T.,Nankai University | Wang H.-T.,Nanjing University
Optics Letters | Year: 2013

The focal electric fields for a 4π high numerical aperture (NA) focusing system with both the doughnut and higherorder Laguerre-Gaussian (LG) radially polarized (RP) beams are investigated in the case of NA 1, and the full width at half-maximum values of the focal spots are calculated. Compared with the single-lens high NA focusing configuration, a sharper spot, whose size is reduced efficiently in the transverse as well as the axial direction, can be formed. Such size reduction is attributed to not only the destruction interference of the longitudinal component caused by the π phase shift between any two adjacent rings of the incident higher-order LG RP beam coming from one particular direction but also the perfect destruction interference of the radial component formed by the two counter-propagating incident beams. © 2013 Optical Society of America.

Xu B.,Nanjing University
Zhen ci yan jiu = Acupuncture research / [Zhongguo yi xue ke xue yuan Yi xue qing bao yan jiu suo bian ji] | Year: 2010

To explore the relationship between the effect of electroacupuncture (EA) and EA of different layer tissues of the acupoint area and different acupoints in upregulating mean arterial pressure (MAP) and heart rate (HR) in hypotension plus bradycardia rats. A total of 200 SD rats were used in the present study. Bradycardia plus hypotension model was established by intravenous injection of 0.4% propranolol (0.4 mg/100 g, maintaining dosage 0.025 mg/100 g per minute). EA (2 Hz/15 Hz, 5 mA) was applied to (1) right "Daling" (PC7) and "Jiexi" (ST 41), "Ximen" (PC 4) and "Housanli" (ST 36), "Quze" (PC 3) and "Dubi" (ST 35) which have a similar tissue structure, and are located in the upper and lower limbs and different meridians, and non-acupoint [3 mm left-superior to the "Tianshu" (ST 25)], (2) skin, muscle layer and periosteum part of "Ximen" (PC4), (3) skin, muscle layer and periosteum of "Housanli" (ST36) for 15 min. The HR and MAP were recorded by using a multi-channel physiological signal sampling-processing system. (1) In comparison with the model group, the percentages of the increased HR and MAP in the "Ximen" (PC4), "Quze" (PC3), "Housanli" (ST 36) and "Jiexi" (ST41) groups, PC 4-skin, PC 4-muscle, PC 4-periosteum, ST 36-skin, ST 36-muscle and ST 36 periosteum groups, and the increased HR in the "Dubi" (ST 35) group were upregulated significantly (P < 0.05, P < 0.01). The percentages of the increased HR and MAP were significantly higher in the "Quze" (PC3) and "Ximen" (PC4) groups than in the "Daling" (PC7) group (P < 0.01), and the increased HR evidently higher in the "Housanli" (ST36) and "Jiexi" (ST41) groups than in the "Dubi" (ST35) group (P < 0.01), suggesting different effects of EA stimulation of different acupoints in the same one meridian. No significant differences were found among the "Ximen" (PC4), "Quze" (PC3), "Housanli" (ST36) and "Jiexi" (ST 41) groups, and between the "Daling" (PC7) and model groups, and between the non-acupoint and model groups in the rising rates of both HR and MAP (P > 0.05). (2) Regarding the effects of EA of different tissue layers in "Ximen" (PC4) and "Housanli" (ST36) areas, the rising rates of HR were markedly higher in the PC 4-skin group than in the "Ximen" (PC4), PC4-muscle and PC 4-periosteum groups (P < 0.01), and considerably higher in the "Housanli" (ST36), ST 36-skin, and ST 36-muscle groups than in ST 36-periosteum group (P < 0.05). The rising rates of MAP were significantly higher in the PC 4-skin and PC 4-muscle groups than in the "Ximen" (PC4) and PC4-periosteum groups (P < 0.01), and considerably higher in the ST36-skin group than in the "Housanli" (ST36), ST36-muscle and ST36-periosteum groups (P < 0.01), suggesting different effects of EA stimulation of different tissue layers in the same one acupoint. No significant differences were found between the "Ximen" (PC 4) and PC 4-muscle groups, among the "Housanli" (ST36), ST36-skin and ST 36-muscle groups in the rising rates of HR, between the "Ximen" (PC 4) and PC4-periosteum groups, and among the "Housanli" (ST36), ST 36-muscle and ST36-periosteum groups in the rising rates of MAP (P > 0.05). (3) The effect of the PC 4-skin group was significantly superior to that of the ST 36-skin group in increasing HR (P < 0.01), and the effect of the PC 4-muscle group was obviously stronger than that of the ST 36-muscle group in raising MAP (P < 0.01), suggesting different therapeutic effects of EA stimulation of the similar tissue in different meridian-acupoints. The effects of the "Ximen"(PC4) and "Housanli" (ST36) groups in raising both HR and MAP, and that of the PC 4-muscle and ST 36-muscle groups in upregulating HR, and that of the PC 4-periosteum and ST 36-periosteum groups in raising MAP were comparable (P > 0.05). EA of different acupoints of the same one meridian, the similar structure of different meridian acupoints and different tissue layers of the same one acupoint have their own relatively specific effects in upregulating HR and MAP in hypotension plus bradycardia rats.

Li F.,Japan National Institute of Advanced Industrial Science and Technology | Li F.,University of Tokyo | Zhang T.,Japan National Institute of Advanced Industrial Science and Technology | Zhou H.,Japan National Institute of Advanced Industrial Science and Technology | And 2 more authors.
Energy and Environmental Science | Year: 2013

A lot of attention has been paid to Li-O2 batteries in recent years, due to the huge potential specific energy and energy density, and they are extensively studied around the world. Much advance has been achieved, however, the fundamental understanding is still insufficient and challenges remain. Here, we provide a specific perspective on the development of non-aqueous Li-O2 batteries excluding those with aqueous, ionic liquid, hybrid, and solid-state electrolytes, because non-aqueous Li-O 2 batteries possess a relatively simple configuration and the research on non-aqueous Li-O2 batteries is the most active of all Li-O2 batteries. The discussion will be focused on non-aqueous electrolytes, cathode catalysts, and anodes, and corresponding perspectives are provided at the end. This journal is © The Royal Society of Chemistry 2013.

Yang J.-N.,Nanjing University
Evolutionary Ecology Research | Year: 2013

Questions: Is ageing evolutionarily adaptive? Can programmed ageing widely evolve as altruism in viscous populations (i.e. widely distributed populations with limited offspring dispersal) in a changing environment? Features of model: The model is individual-based. The probabilities of survival and reproduction are determined by abilities, and abilities increase with both inherited abilities and age-related abilities, so the old can survive and reproduce even if they are genetically less adapted to the environment (termed 'ability conflict'). Inherited traits are determined by multiple independent loci; thus active ageing can enhance the local accumulation of adaptive inherited abilities in viscous populations. Ranges of key variables: Dispersal varied from 0 (no dispersal) to 1 (global). The probability of environment-change during each calculation cycle varied from 0 to 1. Conclusions: Altruistic ageing evolves in structured viscous biological populations with ability conflict in a changing environment to allow the survival of genetically fitter young progenies. To evolve altruistic ageing requires no more environmental change than does sex, suggesting that the generality of altruistic ageing should be no less than sex in viscous populations. If selfish mutants appear only at low rates, higher-level selection would be stabilized even if the environment changes slowly. More extrinsic death can decrease ageing rate (intrinsic death rate) to ensure the same expected lifespan in altruistic ageing, providing testable predictions against traditional ageing theories. My individual-based model also shows how traditional mathematical population genetics largely underestimated the prevalence of group selection. © 2013 Jiang-Nan Yang.

Chen X.,University of Western Australia | Zang W.,Nanjing University | Vimalanathan K.,University of Western Australia | Iyer K.S.,University of Western Australia | Raston C.L.,University of Western Australia
Chemical Communications | Year: 2013

Bubbling H2 into colloidal suspensions of 2D sheets of graphene or h-BN stabilised in water with p-phosphonic acid calix[8]arene, and pre-treated to bind Pd(ii) or Pt(iv) species to their surfaces, is effective in decorating the material with nanoparticles of the noble metals approximately 5 nm in diameter. This journal is © 2013 The Royal Society of Chemistry.

Fjelstad J.,Nanjing University
Journal of Physics A: Mathematical and Theoretical | Year: 2011

Two chiral aspects of the SL(2,ℝ) WZW model in an operator formalism are investigated. First, the meaning of duality, or conjugation, of primary fields is clarified. On a class of modules obtained from the discrete series it is shown, by looking at spaces of two-point conformal blocks, that a natural definition of contragredient module provides a suitable notion of conjugation of primary fields, consistent with known two-point functions. We find strong indications that an apparent contradiction with the Clebsch-Gordan series of SL(2,R), and proposed fusion rules, is explained by non-semi-simplicity of a certain category. Second, results indicating an infinite cyclic simple current group, corresponding to spectral flow automorphisms, are presented. In particular, the subgroup corresponding to even spectral flow provides part of a hypothetical extended chiral algebra resulting in proposed modular invariant bulk spectra. © 2011 IOP Publishing Ltd.

Wang S.,Chinese Academy of Sciences | Ji J.,Chinese Academy of Sciences | Zhou J.-L.,Nanjing University
Astrophysical Journal | Year: 2012

The recent Kepler discovery of KOI-152 reveals a system of three hot super-Earth candidates that are in or near a 4:2:1 mean motion resonance. It is unlikely that they formed in situ; the planets probably underwent orbital migration during the formation and evolution process. The small semimajor axes of the three planets suggest that migration stopped at the inner edge of the primordial gas disk. In this paper, we focus on the influence of migration halting mechanisms, including migration "dead zones," and inner truncation by the stellar magnetic field. We show that the stellar accretion rate, stellar magnetic field, and the speed of migration in the protoplanetary disk are the main factors affecting the final configuration of KOI-152. Our simulations suggest that three planets may be around a star with low star accretion rate or with high magnetic field. On the other hand, slow type I migration, which decreases to one-tenth of the linear analysis results, favors forming the configuration of KOI-152. Under such a formation scenario, the planets in the system are not massive enough to open gaps in the gas disk. The upper limits of the planetary masses are estimated to be about 15, 19, and 24 M ⊕, respectively. Our results are also indicative of the near Laplacian configurations that are quite common in planetary systems. © 2012. The American Astronomical Society. All rights reserved..

Dai X.,Nanjing University
Nonlinearity | Year: 2011

Let T : (X,B,μ) → (X,B,μ) be an ergodic measure-preserving Borel measurable transformation of a separable metric space X that is not necessarily compact, and suppose that {φn}n≤1:X → ℝ ∪ {-∞} is a T subadditive sequence of B-measurable upper-bounded functions. In this paper, we prove that, if the sets Dφn of φn- discontinuities are of μ-measure 0 for all n ≤ 1 and if the growth rates φ * (x) := lim sup nφ+ 1/n φn(x) > 0 for μ-a.e. x ε X, then φ * (x) < 0 for all points x in the basin BT (μ) of (T , μ). We apply this to considering the Oseledets regular points. © 2011 IOP Publishing Ltd & London Mathematical Society.

Zhang Z.B.,Guizhou University | Chen D.Y.,Guizhou University | Huang Y.F.,Nanjing University
Astrophysical Journal | Year: 2012

A correlation between the peak luminosity and the peak energy has been found by Yonetoku et al. as Lp E 2.0 p, i for 11 pre-Swift long gamma-ray bursts (GRBs). In this study, for a greatly expanded sample of 148 long GRBs in the Swift era, we find that the correlation still exists, but most likely with a slightly different power-law index, i.e., L p E 1.7 p,i. In addition, we have collected 17 short GRBs with necessary data. We find that the correlation of Lp E 1.7 p,i also exists for this sample of short events. It is argued that the radiation mechanism of both long and short GRBs should be similar, i.e., of quasi-thermal origin caused by the photosphere, with the dissipation occurring very near the central engine. Some key parameters of the process are constrained. Our results suggest that the radiation processes of both long and short bursts may be dominated by thermal emission, rather than by the single synchrotron radiation. This might put strong physical constraints on the theoretical models. © 2012 The American Astronomical Society. All rights reserved.

Tian W.-D.,Soochow University of China | Ma Y.-Q.,Soochow University of China | Ma Y.-Q.,Nanjing University
Soft Matter | Year: 2011

We consider the effective interaction between dendrimers affected by pH and counterions of solution as well as terminal modification of dendrimers through the calculation of the free energy with coarse-grained molecular dynamics simulations. We find that the decrease of the pH value can induce the increase in the effective size of dendrimers and that multivalent counterions can lead to like-charged attraction between dendrimers. Under high-valent counterion conditions, the attractive force between the two dendrimers displays the "M"-like profiles induced by the competition of various interactions. Moreover, short modification of surface does not change their trend of aggregation no matter what the terminal monomers of the dendrimers are. Our results are helpful for designing a novel class of dendrimers to achieve optimal functionalities. © 2011 The Royal Society of Chemistry.

Zhang C.-H.,University of Massachusetts Medical School | Zhang C.-H.,Nanjing University | Lifshitz L.M.,University of Massachusetts Medical School | Uy K.F.,University of Massachusetts Medical School | And 3 more authors.
PLoS Biology | Year: 2013

Bronchodilators are a standard medicine for treating airway obstructive diseases, and β2 adrenergic receptor agonists have been the most commonly used bronchodilators since their discovery. Strikingly, activation of G-protein-coupled bitter taste receptors (TAS2Rs) in airway smooth muscle (ASM) causes a stronger bronchodilation in vitro and in vivo than β2 agonists, implying that new and better bronchodilators could be developed. A critical step towards realizing this potential is to understand the mechanisms underlying this bronchodilation, which remain ill-defined. An influential hypothesis argues that bitter tastants generate localized Ca2+ signals, as revealed in cultured ASM cells, to activate large-conductance Ca2+-activated K+ channels, which in turn hyperpolarize the membrane, leading to relaxation. Here we report that in mouse primary ASM cells bitter tastants neither evoke localized Ca2+ events nor alter spontaneous local Ca2+ transients. Interestingly, they increase global intracellular [Ca2+]i, although to a much lower level than bronchoconstrictors. We show that these Ca2+ changes in cells at rest are mediated via activation of the canonical bitter taste signaling cascade (i.e., TAS2R-gustducin-phospholipase Cβ [PLCβ]- inositol 1,4,5-triphosphate receptor [IP3R]), and are not sufficient to impact airway contractility. But activation of TAS2Rs fully reverses the increase in [Ca2+]i induced by bronchoconstrictors, and this lowering of the [Ca2+]i is necessary for bitter tastant-induced ASM cell relaxation. We further show that bitter tastants inhibit L-type voltage-dependent Ca2+ channels (VDCCs), resulting in reversal in [Ca2+]i, and this inhibition can be prevented by pertussis toxin and G-protein βγ subunit inhibitors, but not by the blockers of PLCβ and IP3R. Together, we suggest that TAS2R stimulation activates two opposing Ca2+ signaling pathways via Gβγ to increase [Ca2+]i at rest while blocking activated L-type VDCCs to induce bronchodilation of contracted ASM. We propose that the large decrease in [Ca2+]i caused by effective tastant bronchodilators provides an efficient cell-based screening method for identifying potent dilators from among the many thousands of available bitter tastants. © 2013 Zhang et al.

The aim of peer review is to separate the wheat from the chaff for publication and research funding. In the excessive competition, this mechanism would only select the wheat of mainstream. Up to now, almost all discussions on the consequence of the short-comings of peer review are limited to qualitatively description. I propose a model of "peer-group-assessed-grant-based-funding-system" combined with tenure system and over-competitive research funding review process. It is the first on the quantitatively investigation which dramatizes the current short-comings of the process. My simulation shows that it takes about two or three generations of researchers for the mainstream of a complicated research topic obtaining monopoly supremacy, with only the aid of the mechanism the model described. Based on the computation results, suggestions are proposed to avoid loss of self-correction capability on popularity determined single research direction which could be wrong on very complicated research topics. © 2010 Akadémiai Kiadó, Budapest, Hungary.

Ju H.,Nanjing University
Science China Chemistry | Year: 2011

The first decade of the 21st century has been labeled as "the sensing decade". The functional nanomaterials offer excellent platforms for fabrication of sensitive biosensing devices, including optical and electronic biosensors. A lot of works have focused on the biofunctionalization of different nanomaterials, such as metal nanoparticles, semiconductor nanoparticles and carbon nanostructures, by physical adsorption, electrostatic binding, specific recognition or covalent coupling. These biofunctionalized nanomaterials can be used as catalysts, electronic conductors, optical emitters, carriers or tracers to obtain the amplified detection signal and the stabilized recognition probes or biosensing interface. The designed signal amplification strategies have greatly promoted the development of stable, specific, selective and sensitive biosensors in different fields. This review introduces some novel principles and detection strategies in the area of biosensing, based on functional nanomaterials. The general methods for biofunctionalization of nanomaterials with biomolecules and their biosensing application in immunoassay of protein, DNA detection, carbohydrate analysis and cytosensing are also described. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Wang D.,CAS Dalian Institute of Chemical Physics | Wang D.,Nanjing University | Wang F.,CAS Dalian Institute of Chemical Physics | Song G.,CAS Dalian Institute of Chemical Physics | Li X.,CAS Dalian Institute of Chemical Physics
Angewandte Chemie - International Edition | Year: 2012

Olefinic CiH activation of N-allyl sulfonamides in the presence of [{RhCpCl2}2] (Cp=Me5C5) enabled their oxidative coupling with alkynes to generate 1,2-dihydropyridines, pyridines, and cyclopentenones (see scheme; Ts=p-toluenesulfonyl). The type of highly substituted product formed was controlled by the substitution of the allyl group and the reaction conditions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li G.,Nanjing University | Elderfield H.,University of Cambridge
Geochimica et Cosmochimica Acta | Year: 2013

It is generally accepted that progressive cooling of global climate since the Late Cretaceous results from decreasing partial pressure of atmospheric CO2 (pCO2). However, details on how and why the carbon cycle evolved and how it would affect pCO2 have not been fully resolved. While the long-term decline of pCO2 might be caused by the decrease of volcanic degassing through the negative feedback between pCO2 and silicate weathering, seafloor spreading, the major control of CO2 degassing, seems to have remained relatively constant. Alternative explanation, known as 'uplift driven climate change' hypothesis, proposes that tectonic uplift may have enhanced the sink of atmospheric CO2 by silicate weathering, and thus produced the decline of pCO2. However, increasing weathering sink of CO2 could deplete atmosphere all of its CO2 within several million years while holding volcanic outgassing constant. In this work, major fluxes of long-term carbon cycle are calculated based on a reverse model constrained by marine C, Sr and Os isotopic records and the spreading rate of sea floor. Weathering of island basalt and continental silicate rocks are separated in the new model. The results indicate a long-term decline of island basalt weathering in consistent with the global cooling trend over the past 100 million years. Dramatic changes of the CO2 fluxes associated continental silicate weathering, reverse weathering, volcanic degassing and the growth of organic carbon reservoir have been observed. Disturbance of atmospheric CO2 cycle by these fluxes seems to be maintained by the concomitant adjustments of island basalt weathering that were sensitive to the pCO2 controlled environment factors such as temperature and runoff. The negative feedbacks between pCO2 and weathering of island basalt might have played a significant role in stabilizing the long-term carbon cycle. © 2012 Elsevier Ltd.

Zhang C.,Jinling Institute of Technology | Li G.,Nanjing Forestry University | Wang J.,Nanjing University | Fang J.,Nanjing Agricultural University
Bioinformatics | Year: 2012

Motivation: Trans-acting small interfering RNAs (ta-siRNAs) play an essential role in the regulation of plant gene expression, but relevant reports are still limited. Bioinformatic analyses indicate that many ta-siRNA-producing loci (TASs) are present in plants, implying the existence of as yet undiscovered ta-siRNAs and related regulatory pathways. To expand our knowledge of these plant gene regulators, we applied high-throughput computational and experimental methods to grapevine (Vitis vinifera L.).Results: Based on bioinformatic predictions, we identified 49 TASs from 49 055 small RNA clusters. Using RNA degradome analysis, we experimentally validated 5 TASs, 22 ta-siRNAs and 37 ta-siRNA targets. The cis-activities of ta-siRNAs were also confirmed, which suggested an inactive mechanism of TAS transcription, and a produced mechanism of multiple forms of small RNA from same TAS. We examined the conservation of newly identified ta-siRNA regulatory cascades and found that while the cascade related to vviTAS3 was conserved, cascades related to vviTAS7, vviTAS8, vviTAS9 and vviTAS10 were grape-specific. These results broaden the known scope of ta-siRNA regulation. © The Author 2012. Published by Oxford University Press. All rights reserved.

Zhou H.,Nanjing Institute of Environmental Sciences | Gao C.,Nanjing University
Environmental Management | Year: 2011

Agricultural nonpoint phosphorus (P) pollution is a primary cause of eutrophication in many freshwater systems. Identifying areas that are at high risk for P loss in a watershed and concentrating management efforts on these smaller sections is a more effective method for limiting P loss than implementing general strategies over a broad area. A modified P index scheme was used to assess the risk of P loss and identify critical source areas in the Chaohu Lake watershed on a regional scale. In the new P ranking scheme, soil P sorption index (PSI) and degree of P saturation (DPS) were introduced as source factors to represent the inherent ability of P transport in the soil-water interface. Distance from P sources to Chaohu Lake was also considered as a transport factor to take into account P degradation from source to the final receiving water. The ranking scheme was modified to use available data on the regional scale. P index calculation results showed high spatial variation of P loss risk in the Chaohu Lake watershed. The highest risk areas focused on the downstream parts of the main rivers that discharge into Chaohu Lake. The induction of new components into the P index calculation makes it possible to identify critical source areas of nonpoint P loss on a regional scale, thus allowing decision makers to implement best management practices (BMPs) in such a manner as to minimize P loss to sensitive watercourses. © 2011 Springer Science+Business Media, LLC.

Yao Y.,Fudan University | Yao Y.,Nanjing University
Physical Review B - Condensed Matter and Materials Physics | Year: 2015

The charge photogeneration process in organic molecules is investigated by a quantum heat engine model, in which two molecules are modeled by a two-spin system sandwiched between two bosonic baths. The two baths represent the higherature photon emission source and the lowerature phonon environment, respectively. We utilize the time-dependent density matrix renormalization group algorithm to investigate the quantum dynamics of the model. It is found that the transient energy current flowing through the two molecules exhibits two stages. In the first stage the energy current is of a coherent feature and represents the ultrafast delocalization of the charge-transfer state, and in the second stage a steady incoherent current is established. The power conversion efficiency is significantly high and may reach the maximum value of 93% with optimized model parameters. The long-lived quantum entanglement between the two spins is found to be primarily responsible for the hyperefficiency. © 2015 American Physical Society.

Zhou M.,Nanjing University
Nonlinearity | Year: 2011

In this paper, we show that there are infinitely many M̄ -semi-static homoclinic orbits to Ã(0) under the condition that there exists a cohomology c at the boundary of the flat such that hc(g) > 0 holds for each 0 ≠ g ε H1(M × T,A(0),ℤ). © 2011 IOP Publishing Ltd & London Mathematical Society.

Sun Y.,Nanjing University | Zhang Z.,Peking University
Communications in Mathematical Physics | Year: 2011

In this paper, we establish new a priori estimates for the coupled 2D Navier-Stokes equations and Fokker-Planck equation. As its applications, we prove the global existence of smooth solutions for the coupled 2D micro-macro models for polymeric fluids in the bounded domain. © 2010 Springer-Verlag.

Yang J.-N.,Nanjing University
Journal of Theoretical Biology | Year: 2010

In the lights of the concept of cooperation wholes, I discuss why the differentiation of sperm and ova can occur with a mathematical model. Most of Parker's explanations for anisogamy are not completely proper, because it is proved that sperm competition is neither sufficient nor necessary for anisogamy and cooperation to deal with fertilization risks is the real key to understand the evolution of anisogamy. According to the computer simulation results, the transport of gametes between different individuals, risks of the transport, the consequent inequality of sperm and eggs and competition among different individuals were the main causes of gamete differentiation. But these factors have different roles and effects. The transport risk is the main reason for individuals of different mating types to cooperate and differentiate into sperm and egg producers. The transported gametes have an advantage to evolve into sperm to seek for a larger gamete number over the fixed gametes, because they suffer more risks as they can encounter the same fixed gamete and less sibling competition as they can be dispersed better. Gamete competition among different individuals just causes the transported gametes to become as small as possible if they have already become smaller beyond a critical state. In the final discussion, I further put the evolution of anisogamy into a broader background of levels of selection and of the evolution of cooperation, the most important existential mode of matters that makes life as life. © 2010 Elsevier Ltd. All rights reserved.

Wu T.,Nanjing University | Zhang K.,University of Tennessee at Knoxville
Computers and Operations Research | Year: 2014

In this paper, we study a supply chain network design problem which consists of one external supplier, a set of potential distribution centers, and a set of retailers, each of which is faced with uncertain demands for multiple commodities. The demand of each retailer is fulfilled by a single distribution center for all commodities. The goal is to minimize the system-wide cost including location, transportation, and inventory costs. We propose a general nonlinear integer programming model for the problem and present a cutting plane approach based on polymatroid inequalities to solve the model. Randomly generated instances for two special cases of our model, i.e., the single-sourcing UPL&TAP and the single-sourcing multi-commodity location-inventory model, are provided to test our algorithm. Computational results show that the proposed algorithm can solve moderate-sized problem instances efficiently. © 2013 Elsevier Ltd.

Chen Y.,Nanjing University | Oliver D.S.,University of Oklahoma
SPE Journal | Year: 2012

In the ensemble-based approach to production optimization (EnOpt), a steepest-ascent direction is computed from an ensemble of controls to iteratively improve a set of control settings. The method was shown to work well in maximizing field net present value (NPV) with an ensemble size of 104 on the Brugge SPE comparative test case for closed-loop optimization that had 84 controllable completion intervals (and 3,360 control variables), but performance of the method with smaller ensemble size or on larger problems might be difficult. Without regularization, the crosscovariance between control variables and the objective function is often likely to be dominated by spurious correlations. Because the update to the control variables is proportional to the covariance, spurious correlations will result in poor control settings. We propose a localization method that updates the control setting to optimize the field production while reconciling information from each individual well. The proposed localization method reduces the effect of spurious correlations for improved performance. The Brugge test case is used as an example to show that with covariance localization, greater efficiency could be achieved through the use of a smaller ensemble, or that for a given ensemble size, the optimization results can be improved. Copyright © 2012 Society of Petroleum Engineers.

Tian W.-D.,Soochow University of China | Ma Y.-Q.,Soochow University of China | Ma Y.-Q.,Nanjing University
Soft Matter | Year: 2012

Understanding the mechanism of the escape of non-viral vectors from endosomes is critically important for the development of new gene delivery systems. Coarse-grained molecular dynamics simulations of responsive dendrimers interacting with tensionless and tense lipid membranes were performed to give insight into the gene escape mechanism. It was found that the insertion of a charged dendrimer into a membrane is facilitated by the asymmetric distribution of charged lipids and the strongly charged dendrimer can cause a breakdown of membrane asymmetry. Furthermore, dendrimer adsorption could lead to the drop of critical stress required to disrupt the membrane. We propose that a fundamental way for nanoparticles to penetrate through targeted membranes is endowing them with capabilities to tune the local membrane tension. Finally, an escape mechanism of delivered gene materials from an endosome was suggested: a cooperation between global effect, resulting from osmotic pressure and the increase of dendrimer size in the endosome, and local effects caused by the electrostatic adsorption of dendrimers. © 2012 The Royal Society of Chemistry.

Tian W.-D.,Soochow University of China | Ma Y.-Q.,Soochow University of China | Ma Y.-Q.,Nanjing University
Soft Matter | Year: 2012

Simulations were performed to study the dendrimer-lipid membrane interactions in the context of gene delivery systems via exploring the influence of various pH values. As the pH decreases, dendrimers will adsorb on the negatively charged lipid bilayer, and even induce a hole formation on the membrane. We suggest the fourth generation of dendrimers to be the best candidate for gene delivery because of its low toxicity and high efficiency. Additionally, the hole formation under low pH conditions could lead to an asymmetrical bilayer because it facilitates the flip of the negatively charged lipids in one leaflet of the bilayer. We highlight the importance of the regulable electrostatic interaction by biologically relevant stimuli around the lipid membrane. © 2012 The Royal Society of Chemistry.

Granulosa cells (GCs) are tightly associated with fertility and the fate of ovarian follicles. Mitochondria are the central executers of apoptosis. However, the genetic basis underlying mitochondrial modulation in GCs during the ovarian development is poorly understood. Here, CRISPR/Cas9-mediated genetic screening was used to identify genes conferring mitochondrial metabolism in human GCs. The results uncovered roles for several tumor suppressors, including HBP1, in the augmentation of mitochondrial function. Focused analysis revealed that high-mobility group (HMG)-box transcription factor 1 (Hbp1) levels regulate mitochondrial biogenesis, which is associated with global changes in transcription including Tfam. The systemic or granulosa-specific but not oocyte-specific ablation of Hbp1 promoted follicle growth and oocyte production, and is associated with the reduced apoptotic signals in mouse GCs. Consistent with increased mitochondrial function and attenuated GC apoptosis, the regulation of Hbp1 conferred substantial protection of ovarian reserve. Thus, the results of the present study provide a critical target to understand the control of the reproductive lifespan.Cell Death and Differentiation advance online publication, 20 May 2016; doi:10.1038/cdd.2016.47. © 2016 Macmillan Publishers Limited

Xie J.-W.,Nanjing University | Xie J.-W.,University of Toronto
Astrophysical Journal, Supplement Series | Year: 2014

Following on from Paper I in this series, I report the confirmation of a further 30 planets in 15 multiple-planet systems via transit timing variations (TTVs), using the publicly available Kepler light curves (Q0-Q16). All 15 pairs are near first-order mean motion resonances, showing sinusoidal TTVs consistent with theoretically predicted periods, which demonstrate they are orbiting and interacting in the same systems. Although individual masses cannot be accurately extracted based only on TTVs (because of the well known degeneracy between mass and eccentricity), the measured TTV phases and amplitudes can still place relatively tight constraints on their mass ratios and upper limits on their masses, which confirm their planetary nature. Some of these systems (KOI-274, KOI-285, KOI-370, and KOI-2672) are relatively bright and thus suitable for further follow-up observations. © 2014. The American Astronomical Society. All rights reserved..

Wang J.,Yale University | Fischer D.A.,Yale University | Xie J.-W.,Nanjing University | Ciardi D.R.,NASA
Astrophysical Journal | Year: 2014

Almost half of the stellar systems in the solar neighborhood are made up of multiple stars. In multiple-star systems, planet formation is under the dynamical influence of stellar companions, and the planet occurrence rate is expected to be different from that of single stars. There have been numerous studies on the planet occurrence rate of single star systems. However, to fully understand planet formation, the planet occurrence rate in multiple-star systems needs to be addressed. In this work, we infer the planet occurrence rate in multiple-star systems by measuring the stellar multiplicity rate for planet host stars. For a subsample of 56 Kepler planet host stars, we use adaptive optics (AO) imaging and the radial velocity (RV) technique to search for stellar companions. The combination of these two techniques results in high search completeness for stellar companions. We detect 59 visual stellar companions to 25 planet host stars with AO data. Three stellar companions are within 2″ and 27 within 6″. We also detect two possible stellar companions (KOI 5 and KOI 69) showing long-term RV acceleration. After correcting for a bias against planet detection in multiple-star systems due to flux contamination, we find that planet formation is suppressed in multiple-star systems with separations smaller than 1500 AU. Specifically, we find that compared to single star systems, planets in multiple-star systems occur 4.5 ± 3.2, 2.6 ± 1.0, and 1.7 ± 0.5 times less frequently when a stellar companion is present at a distance of 10, 100, and 1000 AU, respectively. This conclusion applies only to circumstellar planets; the planet occurrence rate for circumbinary planets requires further investigation. © 2014. The American Astronomical Society. All rights reserved.

Chen L.,Chinese Academy of Sciences | Chen L.,Nanjing University
Astrophysical Journal | Year: 2014

In this paper, spectral energy distributions (SED) of both synchrotron and inverse Compton (IC) components of a sample of Fermi bright blazars are fitted by a log-parabolic law. The second-degree term of the log parabola measures the curvature of an SED. We find a statistically significant correlation between the synchrotron peak frequency and its curvature. This result is in agreement with the theoretical prediction and confirms previous studies that dealt with a single source with observations at various epochs or a small sample. If a broken power law is employed to fit the SED, the difference between the two spectral indices (i.e., |α2-α1|) can be considered a "surrogate" of the SED curvature. We collect data from the literature and find a correlation between the synchrotron peak frequency and the spectral difference. We do not find a significant correlation between the IC peak frequency and its curvature, which may be caused by a complicated seed photon field. It is also found that the synchrotron curvatures are on average larger than those of IC curvatures, and there is no correlation between these two parameters. As suggested by previous works, both the log-parabolic law of the SED and the above correlation can be explained by statistical and/or stochastic particle accelerations. Based on a comparison of the slops of the correlation, our result seems to favor stochastic acceleration mechanisms and emission processes. Additional evidence, including SED modeling, particle acceleration simulation, and comparisons between some predictions and empirical relations/correlations, also seems to support the idea that the electron energy distribution (and/or synchrotron SED) may be log-parabolic. © 2014. The American Astronomical Society. All rights reserved.

Xia C.,Catholic University of Leuven | Keppens R.,Catholic University of Leuven | Guo Y.,Nanjing University
Astrophysical Journal | Year: 2014

The magnetic configuration hosting prominences and their surrounding coronal structure is a key research topic in solar physics. Recent theoretical and observational studies strongly suggest that a helical magnetic flux rope is an essential ingredient to fulfill most of the theoretical and observational requirements for hosting prominences. To understand flux rope formation details and obtain magnetic configurations suitable for future prominence formation studies, we here report on three-dimensional isothermal magnetohydrodynamic simulations including finite gas pressure and gravity. Starting from a magnetohydrostatic corona with a linear force-free bipolar magnetic field, we follow its evolution when introducing vortex flows around the main polarities and converging flows toward the polarity inversion line near the bottom of the corona. The converging flows bring the feet of different loops together at the polarity inversion line, where magnetic reconnection and flux cancellation happen. Inflow and outflow signatures of the magnetic reconnection process are identified, and thereby the newly formed helical loops wind around preexisting ones so that a complete flux rope grows and ascends. When a macroscopic flux rope is formed, we switch off the driving flows and find that the system relaxes to a stable state containing a helical magnetic flux rope embedded in an overlying arcade structure. A major part of the formed flux rope is threaded by dipped field lines that can stably support prominence matter, while the total mass of the flux rope is in the order of 4-5× 1014 g. © 2014. The American Astronomical Society. All rights reserved..

Huang Z.,Nanjing University
Computers and Mathematics with Applications | Year: 2010

This paper illustrates that the conditions and the main proof of two main theorems of Verma [R.U. Verma, The over-relaxed proximal point algorithm based on H-maximal monotonicity design and applications, Computers and Mathematics with Applications 55 (2008) 2673-2679] concerning the strong convergence of the over-relaxed proximal point algorithm for H-maximal monotone mappings in Hilbert spaces are incorrect. © 2010 Elsevier Ltd. All rights reserved.

Keppens R.,Catholic University of Leuven | Keppens R.,Nanjing University | Xia C.,Catholic University of Leuven
Astrophysical Journal | Year: 2014

We present numerical simulations in 2.5D settings where large-scale prominences form in situ out of coronal condensation in magnetic dips, in close agreement with early as well as recent reporting of funnel prominences. Our simulation uses full thermodynamic magnetohydrodynamics with anisotropic thermal conduction, optically thin radiative losses, and parameterized heating as main ingredients to establish a realistic arcade configuration from chromosphere to corona. The chromospheric evaporation, especially from transition region heights, ultimately causes thermal instability, and we witness the growth of a prominence suspended well above the transition region, continuously gaining mass and cross-sectional area. Several hours later, the condensation has grown into a structure connecting the prominence-corona transition region with the underlying transition region, and a continuous downward motion from the accumulated mass represents a drainage that matches observational findings. A more dynamic phase is found as well, with coronal rain, induced wave trains, and even a reconnection event when the core prominence plasma weighs down the field lines until a flux rope is formed. The upper part of the prominence is then trapped in a flux-rope structure, and we argue for its violent kink-unstable eruption as soon as the (ignored) length dimension would allow for ideal kink deformations. © 2014. The American Astronomical Society. All rights reserved.

Mu Y.,Nanjing University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2016

In this paper, we study the low Mach number limit of the compressible Hall-magnetohydrodynamic equations. It is justified rigorously that, for the well-prepared initial data, the classical solutions of the compressible Hall-magnetohydrodynamic equations converge to that of the incompressible Hall-magnetohydrodynamic equations as the Mach number tends to zero. © 2016, Springer International Publishing.

Suhara T.,National Institute of Technology, Matsue College | Funaki Y.,Accelerator Centre | Zhou B.,Nanjing University | Horiuchi H.,Osaka University | Tohsaki A.,Osaka University
Physical Review Letters | Year: 2014

We present a new picture that the α-linear-chain structure for C12 and O16 has one-dimensional α condensate character. The wave functions of linear-chain states that are described by superposing a large number of Brink wave functions have extremely large overlaps of nearly 100% with single Tohsaki-Horiuchi-Schuck-Röpke wave functions, which were proposed to describe the α condensed "gaslike" states. Although this new picture is different from the conventional idea of the spatial localization of α clusters, the density distributions are shown to have localized α clusters due to the inter-α Pauli repulsion. © 2014 American Physical Society.

We perform molecular dynamics simulations of supercritical water (SCW) with a wide range of densities along a near critical isotherm using the simple point charge extended (SPC/E) pair potential in order to study the entropy and the solvation shell structure around a central water molecule. It is shown that both the translational and orientational two-particle correlation entropy terms can serve as the metrics of the translational-orientational structural orders in water and it is revealed that the translational structural order is very sensitive to the density variation in the gas-like and liquid-like region, while the orientational structural order is much more dependent upon compression in the medium-density SCW region. The comparison of the magnitudes of the full thermodynamic excess entropy and two-particle correlation entropy confirms the recent findings that the many-body terms other than two-body ones also present significant and non-neglectable contributions to the full excess entropy for the highly anomalous fluids like water. The analysis of entropy terms as a function of intermolecular distance and the orientational distribution functions as well as the three-dimensional spatial distribution functions indicate that the structural order occurs only in a much more diffused first solvation shell due to the elongated hydrogen bonds under supercritical conditions. It is revealed that no obvious second or higher neighbor shells occur in SCW, in contrast with the feature of normal liquid water that the anomalous decrease of translational order upon compression occurs mainly in the second shell. © 2012 American Institute of Physics.

Wang X.-Y.,Texas A&M University | Wang X.-Y.,Nanjing University | Avendano C.,Texas A&M University | Dunbar K.R.,Texas A&M University
Chemical Society Reviews | Year: 2011

The study of paramagnetic compounds based on 4d and 5d transition metals is an emerging research topic in the field of molecular magnetism. An essential driving force for the interest in this area is the fact that heavier metal ions introduce important attributes to the physical properties of paramagnetic compounds. Among the attractive characteristics of heavier elements vis-à-vis magnetism are the diffuse nature of their d orbitals, their strong magnetic anisotropy owing to enhanced spin-orbit coupling, and their diverse structural and redox properties. This critical review is intended to introduce readers to the topic and to report recent progress in this area. It is not fully comprehensive in scope although we strived to include all relevant topics and a large subset of references in the area. Herein we provide a survey of the history and current status of research that has been conducted on the topic of second and third row transition metal molecular magnetism. The article is organized according to the nature of the precursor building blocks with special topics being highlighted as illustrations of the special role of heavier transition metal ions in the field. This paper is addressed to readers who are interested in molecular magnetism and the application of coordination chemistry principles to materials synthesis (231 references). © The Royal Society of Chemistry 2011.

Dai W.,Nanjing University
Journal of Computational Information Systems | Year: 2011

Heavy-tailed distribution (HTD) and long-range dependence (LRD) have appeared in the studies of telecommunication, finance, and etc. However, the truncation of a heavy-tailed random variable is inevitable in a computer and network simulation due to the hardware and software limitations such as numbering format of binary digits and pseudo random number generators. Thus a natural issue arises: how well the approximation of a concerned objective in a simulation will be if a truncated random variable is used to replace the original heavy-tailed one? As pointed out in this paper, the difference of the means (or variances) between the truncated version and the original one will still be infinite if the original random variable is heavily tailed with infinite mean and/or variance, which indicates that the truncated approximation may be not consistent with what should be if the HTD/LRD assumptions are imposed. So, based on this observation and our previously established approximation theory via reflecting Gaussian process (RGP) with or without LRD, we can provide more reasonable interpretations to some well-known large-scale computer and statistical experiments in characterizing the superposition of internet traffic sources, which clarify that the findings in these simulations should be more close to the reality but not to the mathematical assumptions about HTD/LRD, which are imposed in their models and analysis. Hence our findings smooth, to some extent, the gaps between HTD/LRD theory and real-world simulations. More importantly, our findings also indicate that it is more suitable to use the truncated version of a heavy-tailed random variable in a simulation and related analysis in order to be more consistent with reality and to avoid more complicated discussions via HTD/LRD theory. Copyright © 2011 Binary Information Press.

Wang Y.,Nanjing University of Aeronautics and Astronautics | Chen S.,Nanjing University of Aeronautics and Astronautics | Zhou Z.-H.,Nanjing University
IEEE Transactions on Neural Networks and Learning Systems | Year: 2012

The cluster assumption, which assumes that 'similar instances should share the same label,' is a basic assumption in semi-supervised classification learning, and has been found very useful in many successful semi-supervised classification methods. It is rarely noticed that when the cluster assumption is adopted, there is an implicit assumption that every instance should have a crisp class label assignment. In real applications, however, there are cases where it is difficult to tell that an instance definitely belongs to one class and does not belong to other neighboring classes. In such cases, it is more adequate to assume that 'similar instances should share similar label memberships' rather than sharing a crisp label assignment. Here 'label memberships' can be represented as a vector, where each element corresponds to a class, and the value at the element expresses the likelihood of the concerned instance belonging to the class. By adopting this modified cluster assumption, in this paper we propose a new semi-supervised classification method, that is, semi-supervised classification based on class membership (SSCCM). Specifically, we try to solve the decision function and adequate label memberships for instances simultaneously, and constrain that an instance and its 'local weighted mean' (LWM) share the same label membership vector, where the LWM is a robust image of the instance, constructed by calculating the weighted mean of its neighboring instances. We formulate the problem in a unified objective function for the labeled, unlabeled data and their LWMs based on the square loss function, and take an alternating iterative strategy to solve it, in which each step generates a closed-form solution, and the convergence is guaranteed. The solution will provide both the decision function and the label membership function for classification, their classification results can verify each other, and the reliability of semi-supervised classification learning might be enhanced by checking the consistency between those two predictions. Experiments show that SSCCM obtains encouraging results compared to state-of-the-art semi-supervised classification methods. © 2012 IEEE.

Zhang S.,Zhejiang Normal University | Zhang S.,Nanjing University
Applied Intelligence | Year: 2011

Data preparation is an important step in mining incomplete data. To deal with this problem, this paper introduces a new imputation approach called SN (Shell Neighbors) imputation, or simply SNI. The SNI fills in an incomplete instance (with missing values) in a given dataset by only using its left and right nearest neighbors with respect to each factor (attribute), referred them to Shell Neighbors. The left and right nearest neighbors are selected from a set of nearest neighbors of the incomplete instance. The size of the sets of the nearest neighbors is determined with the cross-validation method. And then the SNI is generalized to deal with missing data in datasets with mixed attributes, for example, continuous and categorical attributes. Some experiments are conducted for evaluating the proposed approach, and demonstrate that the generalized SNI method outperforms the kNN imputation method at imputation accuracy and classification accuracy. © 2010 Springer Science+Business Media, LLC.

Allelic ratio of an SNP has been used for prenatal diagnosis of fetal trisomy 21 by MALDI-TOF mass spectrometry (MS). Because MALDI-TOF MS is challenging in quantification performance, pyrosequencing was proposed to replace MS by better quantification of allelic ratios. To achieve a simple and rapid clinical diagnostic, PCR with "HpH Buffer" (a buffer with a high pH) was developed to directly amplify amniotic fluid. By the established assay, 114 samples of amniotic fluid were analyzed by pyrosequencing five SNPs of each sample; the allelic ratios of euploid heterozygotes were thus calculated to determine the cut-off values for prenatal diagnosis of trisomy 21. The panel of five SNPs were high in heterozygosity so that at least one heterozygote was found in each sample, and 86% of the samples had at least two heterozygotes, giving a nearly 100% sensitivity (population coverage) of the assay. By using the cut-off values of each SNP, 20 pre-diagnosed clinical samples were detected as trisomy 21 carriers with a confidence level over 99%, indicating that our method and karyotyping analysis were consistent in results. In conclusion, this pyrosequencing-based approach, coupled with direct amplification of amniotic fluid, is accurate in quantitative genotyping and simple in operation. We believe that the approach could be a promising alternative to karyotyping analysis in prenatal diagnosis.

Huang B.,Nanjing Audit University | Wei D.-K.,Hunan University of Science and Technology | Li H.-X.,Nanjing University | Zhuang Y.-L.,Nanjing Audit University
Information Sciences | Year: 2013

Interval-valued intuitionistic fuzzy information systems are generalizations of conventional fuzzy-valued information systems. We introduce a dominance relation in the framework of interval-valued intuitionistic fuzzy information systems to come up with the concept we call a dominance-based interval-valued intuitionistic fuzzy information system (DIIFIS). This system is used to establish a dominance-based rough set model, which is grounded primarily on the substitution of the indiscernibility relation in the classic rough set theory with the aforementioned dominance-based relation. This relation is defined by the score and accuracy of interval-valued intuitionistic fuzzy value. To simplify knowledge representation and extract useful and simple dominance-based interval-valued intuitionistic fuzzy rules, we present two attribute reduction approaches to eliminating redundant information. To demonstrate the potential of these approaches, we apply them to computer auditing risk assessment, decision-making problems in wealth management, and pattern classification. Our findings confirm that the proposed rough set model is an effective means of extracting knowledge from dominance-based interval-valued intuitionistic fuzzy information systems. © 2012 Elsevier Inc. All rights reserved.

Tan L.-L.,Jilin University | Li H.,Beijing Institute of Technology | Tao Y.,Jilin University | Zhang S.X.-A.,Jilin University | And 3 more authors.
Advanced Materials | Year: 2014

A study was conducted to create pillar[5]arene-based supramolecular organic frameworks for highly selective CO2-capture at ambient conditions. Pillar[5]arene (P5) supramolecular organic framework (SOF) was obtained by the slow addition of H2O into a CH2 Cl2 solution of P5 with stirring. The corresponding scanning electron microscopy (SEM) image showed that the P5-SOF materials were bar-shaped, providing direct insight into the formation of SOFs. Thermogravimetric analysis (TGA) of activated P5-SOF showed a rapid weight loss of solvent molecules up to 270 °C, which corresponded to the liberation of approximately 0.5 acetone molecules trapped inside the P5 cavity followed by a plateau region up to 370 °C where the material began decomposing.

Zhou Z.-H.,Nanjing University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In many real-world applications there are usually abundant unlabeled data but the amount of labeled training examples are often limited, since labeling the data requires extensive human effort and expertise. Thus, exploiting unlabeled data to help improve the learning performance has attracted significant attention. Major techniques for this purpose include semi-supervised learning and active learning. These techniques were initially developed for data with a single view, that is, a single feature set; while recent studies showed that for multi-view data, semi-supervised learning and active learning can amazingly well. This article briefly reviews some recent advances of this thread of research. © 2012 Springer-Verlag.

Sinclair A.,University of California at Berkeley | Srivastava P.,University of California at Berkeley | Yin Y.,Nanjing University
Proceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS | Year: 2013

The hard core model in statistical physics is a probability distribution on independent sets in a graph in which the weight of any independent set I is proportional to λ I, where λ > 0 is the vertex activity. We show that there is an intimate connection between the connective constant of a graph and the phenomenon of strong spatial mixing (decay of correlations) for the hard core model; specifically, we prove that the hard core model with vertex activity λ < λc(Δ+1) exhibits strong spatial mixing on any graph of connective constant Δ, irrespective of its maximum degree, and hence derive an FPTAS for the partition function of the hard core model on such graphs. Here λc(d) ..= dd/ (d-1)d+1is the critical activity for the uniqueness of the Gibbs measure of the hard core model on the infinite d-ary tree. As an application, we show that the partition function can be efficiently approximated with high probability on graphs drawn from the random graph model G (n, d/n) for all λ < e/d, even though the maximum degree of such graphs is unbounded with high probability. We also improve upon Weitz's bounds for strong spatial mixing on bounded degree graphs [30] by providing a computationally simple method which uses known estimates of the connective constant of a lattice to obtain bounds on the vertex activities λ for which the hard core model on the lattice exhibits strong spatial mixing. Using this framework, we improve upon these bounds for several lattices including the Cartesian lattice in dimensions 3 and higher. Our techniques also allow us to relate the threshold for the uniqueness of the Gibbs measure on a general tree to its branching factor [15]. Copyright © 2013 by The Institute of Electrical and Electronics Engineers, Inc.

Liang Q.,Shaoxing University | Yan Y.,Shaoxing University | Dong J.,Nanjing University
Optics Letters | Year: 2011

The propagation of a wave packet in a honeycomb photonic lattice has been studied using the time-dependent wave packet dynamics. It is found that the wave packet, superposed from the positive and negative energy modes at the vicinity of the two inequivalent Dirac points, can transform into a double-ring structure, which is caused by the interference between the two positive and negative energy modes around the Dirac points and is closely related to the Zitterbewegung (ZB). Also, a possible way to detect the ZB effect is proposed in the honeycomb photonic lattice. © 2011 Optical Society of America.

Chen G.,Nanjing University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

QCD amplitudes with many external fields have been studied for a long time. At tree-level, the amplitudes can be obtained effectively by the Britto-Cachazo-Feng-Witten (BCFW) recursion relations. In this article, we extend the BCFW relations to the QCD amplitude of which the external fields are all massive or include only one massless line. We find such amplitude can be split into two parts and each part of the amplitude is of some correlated spin configuration between the two shifted lines. After choosing proper momentum shift scheme, we can show that each part is constructible directly. Hence, we can obtain a general procedure for the amplitudes in QCD by the BCFW recursion relations. We apply the procedure to several amplitudes as examples. We find such methods are very efficient when there are many massive external fields in the amplitudes. © 2011 American Physical Society.

Xie J.-W.,Nanjing University | Xie J.-W.,University of Toronto
Astrophysical Journal, Supplement Series | Year: 2013

We extract transit timing variation (TTV) signals for 12 pairs of transiting planet candidates that are near first-order mean motion resonances (MMR), using publicly available Kepler light curves (Q0-Q14). These pairs show significant sinusoidal TTVs with theoretically predicted periods, which demonstrate these planet candidates are orbiting and interacting in the same system. Although individual masses cannot be accurately extracted based only on TTVs because of the well-known degeneracy between mass and eccentricity, TTV phases and amplitudes can still place upper limits on the masses of the candidates, confirming their planetary nature. Furthermore, the mass ratios of these planet pairs can be relatively tightly constrained using these TTVs. The planetary pair in KOI 880 seems to have particularly high mass and density ratios, which might indicate very different internal compositions of these two planets. Some of these newly confirmed planets are also near MMR with other candidates in the system, forming unique resonance chains (e.g., KOI 500). © 2013. The American Astronomical Society. All rights reserved..

Sheng J.,University of Arkansas | Khadka U.,University of Arkansas | Xiao M.,University of Arkansas | Xiao M.,Nanjing University
Physical Review Letters | Year: 2012

We have experimentally observed optical multistability (OM) in an optical ring cavity containing three-level Λ-type Doppler-broadened rubidium atoms. The shape of the OM curve can be significantly modified by changing the power of the control laser field. An all-optical multistate switching or coding element is realized and flexibly controlled by adding a pulse sequence to the input (probe) intensity. © 2012 American Physical Society.

Zhu G.,Nanjing University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

We show that quasi-closed subwavelength electromagnetic rectangular resonators can be constructed using stacked dielectric-plasmonic bilayer structures, in an analogy to the dielectric resonators formed by materials with large permittivity commonly seen in microwave engineering. We establish an analytic framework for designing such subwavelength resonators by providing formulas for calculating the resonant frequency and the radiation/ material loss Q-factors of the fundamental mode. The provided analytic formulas yield accurate results when compared with the numerical simulations for a broad range of design parameter sets. The proposed stack resonator in principle can be made arbitrarily small and, in the absence of material loss, can have Q-factors larger than 105. © 2012 Optical Society of America.

Xu F.,Nanjing University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

By the Laplace-Runge-Lenz (LRL) vector, we analyzed perihelion precessions of orbit with arbitrary eccentricity from perturbations of 1) power law central force and 2) fThusmagnetic-like force. Exact and analytically closed expressions for the precession rate are derived in both cases. In the central force case, we give a further expansion expression of precession rate in orders of eccentricity, and a rule judging pro- or retrograde precession is also given. We applied the result of central force to precessions of a planet in 1) Schwarzschild space-time, for which the formula for the Mercurys 43"/century is reproduced, and 2) spherically distributed dark matter, for which we find a formula that is a generalization of the result derived by others for circular orbit. In the magnetic case, the use of the LRL vector proves to be simple and efficient. An example of magnetic-like perturbation is also discussed. © 2011 American Physical Society.

Wu X.-F.,Chinese Academy of Sciences | Wu X.-F.,Nanjing University | Hou S.-J.,Xiamen University | Lei W.-H.,Huazhong University of Science and Technology
Astrophysical Journal Letters | Year: 2013

A particularly interesting discovery in observations of GRB 121027A is that of a giant X-ray bump detected by the Swift/X-Ray Telescope. The X-ray afterglow re-brightens sharply at ≃103 s after the trigger by more than two orders of magnitude in less than 200 s. This X-ray bump lasts for more than 104 s. It is quite different from typical X-ray flares. In this Letter we propose a fall-back accretion model to interpret this X-ray bump within the context of the collapse of a massive star for a long-duration gamma-ray burst. The required fall-back radius of ≃3.5 × 10 10 cm and mass of ≃0.9-2.6 M imply that a significant part of the helium envelope should survive through the mass loss during the last stage of the massive progenitor of GRB 121027A. © 2013. The American Astronomical Society. All rights reserved..

Ying X.N.,Nanjing University
Solid State Communications | Year: 2013

Oxygen nonstoichiometric La1/3Sr2/3FeO 3-δ sample was prepared and investigated by kilohertz mechanical spectroscopy and dielectric spectroscopy from liquid nitrogen to room temperature. Charge order is suppressed in oxygen nonstoichiometric La 1/3Sr2/3FeO3-δ sample. Young's modulus shows conventional hardening with the decrease in temperature. It is different to previous observed lattice softening above charge ordering transition in as-prepared La1/3Sr2/3FeO3-δ sample. A relaxation process is observed in dielectric loss in oxygen nonstoichiometric La1/3Sr2/3FeO3-δ sample with the activation energy of 0.26 eV. It can be explained by electron hopping between Fe3+ and Jahn-Teller distorted Fe4+ ions. An internal friction peak around 130 K is explained similarly by stress induced electron hopping between Fe3+ and Fe4+. This work suggests that Fe4+ is stabilized by the Jahn-Teller distortion in oxygen nonstoichiometric La1/3Sr2/3FeO3-δ ceramic. This is expected to be the reason of charge order suppression in oxygen nonstoichiometric La1/3Sr2/3FeO3-δ sample. © 2013 Elsevier Ltd. All rights reserved.

Liu H.-C.,Tokyo Institute of Technology | Liu L.,Tongji University | Liu N.,Chongqing Jiaotong University | Mao L.-X.,Nanjing University
Expert Systems with Applications | Year: 2012

Failure mode and effects analysis (FMEA) is a widely used risk assessment tool for defining, identifying, and eliminating potential failures or problems in products, process, designs, and services. In traditional FMEA, the risk priorities of failure modes are determined by using risk priority numbers (RPNs), which can be obtained by multiplying the scores of risk factors like occurrence (O), severity (S), and detection (D). However, the crisp RPN method has been criticized to have several deficiencies. In this paper, linguistic variables, expressed in trapezoidal or triangular fuzzy numbers, are used to assess the ratings and weights for the risk factors O, S, and D. For selecting the most serious failure modes, the extended VIKOR method is used to determine risk priorities of the failure modes that have been identified. As a result, a fuzzy FMEA based on fuzzy set theory and VIKOR method is proposed for prioritization of failure modes, specifically intended to address some limitations of the traditional FMEA. A case study, which assesses the risk of general anesthesia process, is presented to demonstrate the application of the proposed model under fuzzy environment. © 2012 Elsevier Ltd. All rights reserved.

Wu D.,Nanjing University
The Journal of chemical physics | Year: 2012

The influences of the anisotropic permittivity and permeability in inner core on the Fano resonance have been investigated in Ag nanoshell by means of Mie scattering theory. The decreased inner core radius can enhance the coupling between superradiant and subradiant dipole modes and hence a distinct Fano profile. With increasing the tangential permittivity or permeability of inner core, the Fano resonance shows a redshift and the magnitude of Fano profile increases. The variation of Fano resonance with anisotropic permeability of the core is much weaker than that induced by anisotropic permittivity. We further find that the combined action of the increased tangential permittivity and permeability of inner core can induce a significant enhancement of Fano resonance in Ag nanoshell. © 2012 American Institute of Physics

Wang X.,Nanjing University
Journal of Applied Physics | Year: 2010

An analytical theory for sound transmitting through apertures that are slits or holes periodically pored on one- or two-dimensional rigid panels is developed in small-aperture approximation, with all coefficients of reflection and transmission given explicitly in concise and easily calculable forms. We utilize acoustical impedance to quantitatively describe the effect of sound diffraction by both surfaces of a perforated slab on the aperture resonance. We show that diffraction induced reactance Xa, which is acoustically inertant (Xa >0) for incident wavelength λ longer than the period ∧ of the perforated slab, can become infinitely large as λ approaches to ∧. We further show that the singularity of Xa not only causes the already known full reflection of acoustic waves at λ= ∧, but also drastically changes the aperture resonance leading to the extraordinary acoustical transmission that was observed in recent experiments. With this understanding, tuning the resonant transmission becomes practically feasible in applications of the resonant transmission phenomenon. © 2010 American Institute of Physics.

We design a dynamic rate scheduling policy of Markov type by using the solution (a social optimal Nash equilibrium point) to a utility-maximization problem over a randomly evolving capacity set for a stochastic system of generalized processorsharing queues in a random environment whose job arrivals to each queue follow a doubly stochastic renewal process (DSRP). Both the random environment and the random arrival rate of each DSRP are driven by a finite state continuous time Markov chain. The scheduling policy optimizes in a greedy fashion with respect to each queue and environmental state. Since the closed-form solution for the performance of such a queuing system under the policy is difficult to obtain, we establish a reflecting diffusion with regime-switching model for its measures of performance. Furthermore, we justify its asymptotic optimality by deriving the stochastic fluid and diffusion limits for the corresponding system under heavy traffic. In addition, we identify a cost function related to the utility function, which is minimized by minimizing the workload process in the diffusion limit. More importantly, our queuing model includes typical systems in the future wireless networks, such as the J -user multi-input multioutput multiple access channel and the broadcast channel under Markov fading with cooperation and admission control as special cases. © 2013 INFORMS.

Nie C.,Nanjing University | Leung H.,Hong Kong Polytechnic University
ACM Transactions on Software Engineering and Methodology | Year: 2011

Combinatorial Testing (CT) involves the design of a small test suite to cover the parameter value combinations so as to detect failures triggered by the interactions among these parameters. To make full use of CT and to extend its advantages, this article first gives a model of CT and then presents a theory of the Minimal Failure-causing Schema (MFS), including the concept of the MFS, proof of its existence, some of its properties, and a method of finding the MFS. Then we propose a methodology for CT based on this MFS theory and the existing research. Our MFS-based methodology emphasizes that CT should work on accurate testing requirements, and has the following advantages: 1) Detect failure to the greatest degree with the least cost. 2) Effectiveness is improved by emphasizing mining of the information in software and making full use of the information gained from test design and execution. 3) Determine the root causes of failures and reveal related faults near the exposed ones. 4) Provide a foundation and model for regression testing and software quality evaluation of CT. A case study is presented to illustrate the MFS-based CT methodology, and an empirical study on a real software developed by us shows that the MFS really exists and the methodology based on MFS can considerably improve CT. © 2011 ACM.

Zhou Z.-H.,Nanjing University
Frontiers of Electrical and Electronic Engineering in China | Year: 2011

Semi-supervised learning and ensemble learning are two important machine learning paradigms. The former attempts to achieve strong generalization by exploiting unlabeled data; the latter attempts to achieve strong generalization by using multiple learners. Although both paradigms have achieved great success during the past decade, they were almost developed separately. In this paper, we advocate that semi-supervised learning and ensemble learning are indeed beneficial to each other, and stronger learning machines can be generated by leveraging unlabeled data and classifier combination. © 2011 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Lian S.,Orange S.A. | Chen X.,Nanjing University
Applied Soft Computing Journal | Year: 2011

In this paper, a media content encryption/decryption algorithm is designed based on a chaos system and neural networks, which generates random sequences with chaos, and encrypts or decrypts media contents with neural networks in a parallel way. In this scheme, different decryption keys can be used to recover the media content into different copies. That is, the decryption operation gets the content containing certain random sequence that can be used as the identification. With respect to this property, the scheme is used for secure content distribution. Taking the audio content for example, it is encrypted by a key at the sender side and decrypted by different keys at the receiver side. The differences between decryption keys lead to different decrypted audio copies. If one customer distributes his copy to other unauthorized customers, the chaotic sequence contained in the copy can tell the illegal customer. The performances, including security, imperceptibility and robustness, are analyzed, and some experimental results are given to show the scheme's practicability. © 2010 Elsevier B.V. All rights reserved.

Ma H.,Nanjing University | Troisi A.,University of Warwick
Advanced Materials | Year: 2014

Direct optical excitation of long-range charge-transfer (CT) states in organic photovoltaics is shown to be feasible, a fact that is ascribed to the very low but non-vanishing oscillator strength of each individual transition and the much higher density of states (DOS) as compared with their short-range counterparts. This finding provides a new framework to interpret the low-energy absorption spectra of photovoltaic devices and to correlate this property with the optoelectronic conversion process in working devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang Y.-F.,Zhejiang Normal University | Wang Y.-F.,California State University, Northridge | Gu Z.-C.,University of California at Santa Barbara | Gong C.-D.,Zhejiang Normal University | And 2 more authors.
Physical Review Letters | Year: 2011

Recent proposals of topological flat band models have provided a new route to realize the fractional quantum Hall effect without Landau levels. We study hard-core bosons with short-range interactions in two representative topological flat band models, one of which is the well-known Haldane model (but with different parameters). We demonstrate that fractional quantum Hall states emerge with signatures of an even number of quasidegenerate ground states on a torus and a robust spectrum gap separating these states from the higher energy spectrum. We also establish quantum phase diagrams for the filling factor 1/2 and illustrate quantum phase transitions to other competing symmetry-breaking phases. © 2011 American Physical Society.

Li Y.,Nanjing University | Wu F.,University College London
Habitat International | Year: 2013

China has recently seen the proliferation of regional plans. This paper tries to understand the development of regional plans from the perspective of state restructuring and changing regional governance. In contrast to conventional wisdom, which predominantly describes China's decentralization, another aspect of 'recentralization' is highlighted here. The paper focuses on a case study of Yangtze River Delta Regional Plan. It is argued that the latest regional plans are used by the central government to coordinate diverse local interests to achieve a more balanced development. However, complex politics between different levels and divisions of government make this plan an impossible project to deliver central regulation on contemporary city-regions. © 2012 Elsevier Ltd.

Based on the results of the operations of del, including the gradient, the curl, and the divergence obtained under nonorthogonal curvilinear coordinate transformations, we present a derivation of the scaling laws for electromagnetic waves, acoustic waves, and matter waves in a framework that is fully unified. Our derivation approach does not involve any tensor analysis or differential element analysis and may serve as an important supplement to those derivation methods established previously. © 2011 Optical Society of America.

A linear scaling quantum chemistry method, generalized energy-based fragmentation (GEBF) approach has been extended to the explicitly correlated second-order Møller-Plesset perturbation theory F12 (MP2-F12) method and own N-layer integrated molecular orbital molecular mechanics (ONIOM) method, in which GEBF-MP2-F12, GEBF-MP2, and conventional density functional tight-binding methods could be used for different layers. Then the long-range interactions in dilute methanol aqueous solutions are studied by computing the binding energies between methanol molecule and water molecules in gas-phase and condensed phase methanol-water clusters with various sizes, which were taken from classic molecular dynamics (MD) snapshots. By comparing with the results of force field methods, including SPC, TIP3P, PCFF, and AMOEBA09, the GEBF-MP2-F12 and GEBF-ONIOM methods are shown to be powerful and efficient for studying the long-range interactions at a high level. With the GEBF-ONIOM(MP2-F12:MP2) and GEBF-ONIOM(MP2-F12:MP2:cDFTB) methods, the diameters of the largest nanoscale clusters under studies are about 2.4 nm (747 atoms and 10 209 basis functions with aug-cc-pVDZ basis set) and 4 nm (3351 atoms), respectively, which are almost impossible to be treated by conventional MP2 or MP2-F12 method. Thus, the GEBF-F12 and GEBF-ONIOM methods are expected to be a practical tool for studying the nanoscale clusters in condensed phase, providing an alternative benchmark for ab initio and density functional theory studies, and developing new force fields by combining with classic MD simulations. © 2013 American Institute of Physics.

Zhao Y.,University of Texas at Austin | Liu B.,University of Texas at Austin | Pan L.,Nanjing University | Yu G.,University of Texas at Austin
Energy and Environmental Science | Year: 2013

Conducting polymer hydrogels (CPHs) represent a unique class of materials that synergize the advantageous features of hydrogels and organic conductors and have been used in many applications such as bioelectronics and energy storage devices. This perspective provides a brief overview of current research activities in the field of three-dimensional (3D) nanostructured CPHs for high-performance electrochemical devices. The synthesis methods of conventional conductive polymers (CPs) and hydrogels are outlined with emphasis on newly developed methods for the preparation of 3D nanostructured CPs and CPHs. Following this discussion is an outline of the applications of 3D CPH nanostructures with particular focus on those applications in which nanostructured CPHs are clearly advantageous over their conventional counterparts. Other potential applications of nanostructured CPHs are also discussed in this perspective along with the main challenges and future research directions for this new class of conductive hydrogels. © The Royal Society of Chemistry 2013.

Liu G.,Brookhaven National Laboratory | Liu G.,Nanjing University | Liu Y.,Brookhaven National Laboratory | Endo S.,Brookhaven National Laboratory
Monthly Weather Review | Year: 2013

Surface momentum, sensible heat, and latent heat fluxes are critical for atmospheric processes such as clouds and precipitation, and are parameterized in a variety of models ranging from cloud-resolving models to largescale weather and climatemodels. However, direct evaluation of the parameterization schemes for these surface fluxes is rare due to limited observations. This study takes advantage of the long-term observations of surface fluxes collected at the Southern Great Plains site by the Department of Energy Atmospheric Radiation Measurement program to evaluate the six surface flux parameterization schemes commonly used in the Weather Research and Forecasting (WRF)model and threeU.S. general circulationmodels (GCMs). The unprecedented 7-yr-longmeasurements by the eddy correlation (EC) and energy balance Bowen ratio (EBBR)methods permit statistical evaluation of all six parameterizationsunder a variety of stability conditions, diurnal cycles, and seasonal variations. The statistical analyses show that themomentumflux parameterization agrees best with the EC observations, followed by latent heat flux, sensible heat flux, and evaporation ratio/Bowen ratio. The overall performance of theparameterizations depends on atmospheric stability, being best under neutral stratification and deteriorating toward both more stable andmore unstable conditions. Further diagnostic analysis reveals that in addition to the parameterization schemes themselves, the discrepancies between observed and parameterized sensible and latent heat fluxes may stem from inadequate use of input variables such as surface temperature, moisture availability, and roughness length. The results demonstrate the need for improving the land surface models and measurements of surface properties, which would permit the evaluation of full land surface models. © 2013 American Meteorological Society.

Zheng G.,Nanjing University | Moskal L.M.,University of Washington | Kim S.-H.,University of Washington
IEEE Transactions on Geoscience and Remote Sensing | Year: 2013

Terrestrial laser scanner (TLS)-based leaf area index (LAI) retrieval is an appealing concept, due to the ability to capture structural information of canopies as 3-D point cloud data (PCD). TLS-based LAI estimation methods promise a nondestructive tool for spatially explicit calibration of LAI estimated by aerial or satellite remote sensing techniques. These methods also overcome the sky condition restrictions of on-ground optical instruments such as hemispherical photography frequently used for LAI estimation. This paper presents a new method for estimating the effective LAI (LAIe) directly from PCD generated by TLS in heterogeneous forests. We converted the 3-D PCD into 2-D raster images, similar to hemispherical photographs, using two geometrical projection techniques in order to estimate gap fraction and LAIe using a linear least squares method. Our results indicated that the TLS-based algorithm was able to capture the variability in LAIe of forest stands with a range of densities. The TLS-based LAIe estimation method explained 89.1% (rmse = 0.01; p < 0.001) of the variation in results from digital hemispherical photographs taken of the same stands and used for validation. The Breusch-Pagan test score confirmed that the stereographic-projection-based TLS LAIe model was more robust compared to the Lambert azimuthal equal-area projection TLS LAIe model. Finally, we explore and show significant relationships between airborne-laser-scanner (ALS)-based and TLS-based LAIe estimates, showing promise for further exploration of utilizing TLS as a calibration tool for ALS. © 1980-2012 IEEE.

Wan X.,Nanjing University | Vishwanath A.,University of California at Berkeley | Vishwanath A.,Lawrence Berkeley National Laboratory | Savrasov S.Y.,University of California at Davis
Physical Review Letters | Year: 2012

Based on density functional calculation using the local density approximation+U method, we predict that osmium compounds such as CaOs 2O 4 and SrOs 2O 4 can be stabilized in the geometrically frustrated spinel crystal structure. They show ferromagnetic order in a reasonable range of the on-site Coulomb correlation U and exotic electronic properties, in particular, a large magnetoelectric coupling characteristic of axion electrodynamics. Depending on U, other electronic phases including a 3D Weyl semimetal and Mott insulator are also shown to occur. © 2012 American Physical Society.

Huang Z.,Tohoku University | Huang Z.,Nanjing University | Zhao D.,Tohoku University
Physics of the Earth and Planetary Interiors | Year: 2013

Much progress has been made on revealing seismic structure and mantle dynamics beneath the United States (US) with the EarthScope/USArray project. Seismic anisotropy revealed by shear-wave splitting studies provides important constraints on constructing geodynamic models with regard to the seismic images, but the shear-wave splitting observations have poor vertical resolution and so their interpretations are often not unique. In this work we used a large number of arrival-time data from local and distant earthquakes recorded by the USArray to determine the first P-wave azimuthal anisotropy tomography of the crust and upper mantle beneath the US. Our results show that fast velocity directions (FVDs) in the lithosphere under the tectonically active areas correlate well with the surface tectonic features, suggesting that the P-wave anisotropy mainly reflects the present deformation. A circular pattern of the FVDs centered in the Great Basin is revealed, which is well consistent with the specific circular shear-wave splitting observations there, suggesting that the anisotropy occurs in the crust and uppermost mantle. In contrast, beneath the stable cratonic region, the FVDs revealed by this study differ from the shear-wave splitting observations but consistent with the features of gravity and magnetic anomalies, indicating that the P-wave FVDs mainly reflect the fossil anisotropy in the lithosphere, whereas the S-wave splitting observations mainly reflect the significant anisotropy in the asthenosphere. The present results shed new light on the seismic anisotropy in the crust and upper mantle and provide new constraints on constructing geodynamic models beneath the US. © 2013 Elsevier B.V.

Zhang K.-J.,Nanjing University | Zhang K.-J.,CAS Guangzhou Institute of Geochemistry
Journal of Geodynamics | Year: 2012

High heat flow, high surface topography, and widespread volcanism indicate that the lithospheric mantle of typical cratonic character of the North China Craton has been seriously destroyed in its eastern half. However, the mechanism of this process remains open to intense debate. Here lithosphere folding-induced lithospheric mantle removal is proposed as a new mechanism for the destruction of the craton. Four main NNE-SSW-striking lithospheric-scale anticlines and synclines are recognized within North China east of the Helan fold-and-thrust belt. The lithosphere folding occurred possibly during the Late Triassic through Jurassic when the Yangzi Craton collided with the North China Craton. It was accompanied or followed by lithospheric dripping, and could have possibly induced the lithosphere foundering of the North China Craton. The lithosphere folding would have modified the lithosphere morphology, creating significant undulation in the lithospheric base and thus causing variations of the patterns of the small-scale convection. It also could have provoked the formation of new shear zones liable to impregnation of magma, producing linear incisions at the cratonic base and resulting in foundering of lithospheric mantle blocks. Furthermore, it generated thickening of the lithosphere or the lower crust and initiated the destabilization and subsequent removal of the lithospheric mantle. © 2011 Elsevier Ltd.

Sang Y.-F.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Sang Y.-F.,Nanjing University
Atmospheric Research | Year: 2012

In this paper, the variability of daily temperature in the Yangtze River Delta (YRD) for the period 1958-2007 was investigated by selecting three typical temperature variables (daily minimum, mean and maximum temperatures) and the diurnal temperature range (DTR). Three variability patterns of daily mean temperature and two variability patterns of daily minimum and maximum temperatures were first classed, and then statistical properties of three temperature variables in 1958-1985 and 1986-2007 were analyzed. After that, temporal trends of three temperature variables and DTR were detected. Finally, the impacts of urbanization on the variability of daily temperature were investigated. Results indicate that: (1) daily mean temperature shows more complex variability than daily minimum and maximum temperatures; (2) in 1986-2007 three temperature variables have bigger mean values but smaller C v (coefficient of variance) values, and are more close to normal probability distribution; (3) three temperature variables show positive trends in 1986-2007, and the increase of daily mean temperature is more due to the increase of daily minimum temperature in the northern YRD but due to daily maximum temperature in the mid and southern YRD; (4) in the mid and southern YRD, daily maximum temperature has bigger increasing magnitude than daily minimum temperature in 1986-2007, causing positive trend of DTR; and (5) rapid urbanization causes normal distribution of three temperature variables, and notably increasing magnitude of daily temperature and DTR in 1986-2007 at the lower reaches of the Yangtze River and the Hangzhou Bay. © 2012 Elsevier B.V.

Wei J.-J.,Chinese Academy of Sciences | Wu X.-F.,Chinese Academy of Sciences | Wu X.-F.,Chinese Center for Antarctic Astronomy | Wu X.-F.,Nanjing University | Melia F.,University of Arizona
Astrophysical Journal | Year: 2013

In this paper, we continue to build support for the proposal to use gamma-ray bursts (GRBs) as standard candles in constructing the Hubble diagram at redshifts beyond the current reach of Type Ia supernova observations. We confirm that correlations among certain spectral and light-curve features can indeed be used as luminosity indicators, and demonstrate from the most up-to-date GRB sample appropriate for this work that the CDM model optimized with these data is characterized by parameter values consistent with those in the concordance model. Specifically, we find that (ωm, ωδ ≈ (0.25+0.05 0.06, 0.75 +0.06 0.05), which are consistent, to within 1, with (0.29, 0.71) obtained from the 9 yr Wilkinson Microwave Anisotropy Probe data. We also carry out a comparative analysis between ta;CDM and the Rh = ct universe and find that the optimal δCDM model fits the GRB Hubble diagram with a reduced ?2 dof ≈ 2.26, whereas the fit using Rh = ct results in a ?2 dof ≈ 2.14. In both cases, about 20% of the events lie at least 2? away from the best-fit curves, suggesting that either some contamination by non-standard GRB luminosities is unavoidable or that the errors and intrinsic scatter associated with the data are being underestimated. With these optimized fits, we use three statistical toolsthe Akaike information criterion, the Kullback information criterion, and the Bayes information criterionto show that, based on the GRB Hubble diagram, the likelihood of Rh = ct being closer to the correct model is ∼85%96%, compared to ∼4%15% for δCDM. © 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

Wu X.,Nanchang University | Xie Y.,Nanjing University | Xie Y.,University of Missouri
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

The phase space of a Hamiltonian system is symplectic. However, the post-Newtonian Hamiltonian formulation of spinning compact binaries in existing publications does not have this property, when position, momentum, and spin variables [X,P,S1,S2] compose its phase space. This may give a convenient application of perturbation theory to the derivation of the post-Newtonian formulation, but also makes classic theories of a symplectic Hamiltonian system a serious obstacle in application, especially in diagnosing integrability and nonintegrability from a dynamical system theory perspective. To completely understand the dynamical characteristic of the integrability or nonintegrability for the binary system, we construct a set of conjugate spin variables and reexpress the spin Hamiltonian part so as to make the complete Hamiltonian formulation symplectic. As a result, it is directly shown with the least number of independent isolating integrals that a conservative Hamiltonian compact binary system with both one spin and the pure orbital part to any post-Newtonian order is typically integrable and not chaotic. And a conservative binary system consisting of two spins restricted to the leading order spin-orbit interaction and the pure orbital part at all post-Newtonian orders is also integrable, independently on the mass ratio. For all other various spinning cases, the onset of chaos is possible. © 2010 The American Physical Society.

Lu X.,Nanjing University | Wang H.,Wuhan University
Elements | Year: 2012

Mining activities have created great wealth, but they have also produced colossal quantities of tailings. An important source of heavy metal contamination, sulfide tailings are usually disposed of in open-air impoundments and thus are exposed to microbial oxidation. Microbial activities greatly enhance sulfide oxidation and result in the release of heavy metals and the precipitation of iron (oxy)hydroxides and sulfates. These secondary minerals in turn influence the mobility of dissolved metals and play important roles in the natural attenuation of heavy metals. Elucidating the microbe-mineral interactions in tailings will help us mitigate the environmental impacts of mining activities.

We present a design of a square invisibility cloak based on triangular transformations. In triangular transformations, certain areas of the cloak are squeezed to be infinitesimal in the virtual space. This results in cloak materials whose constitutive parameters are singular. We show rigorously that these prescribed singular materials can be emulated by metamaterials made of stacked positive-negative index slabs. We use numerical simulations to demonstrate the conceived square cloak, which in principle can be constructed using only homogenous and non-singular materials. The proposed square invisibility cloak suggests another important application of negative index media. © 2013 AIP Publishing LLC.

Zi W.,University of California at Berkeley | Wu H.,University of California at Berkeley | Wu H.,Nanjing University | Toste F.D.,University of California at Berkeley
Journal of the American Chemical Society | Year: 2015

A highly enantioselective dearomative Rautenstrauch rearrangement catalyzed by cationic (S)-DTBM-Segphosgold(I) is reported. This reaction provides a straightforward method to prepare enantioenriched cyclopenta[b]indoles. These studies show vast difference in enantioselectivity in the reactions of propargyl acetates and propargyl acetals in the chiral ligand-controlled Rautenstrauch reaction. © 2015 American Chemical Society.

The p38 MAPK signaling pathway plays a pivotal role in inflammation. Targeting p38 MAPK may be a potential strategy for the treatment of inflammatory diseases. In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK. Moreover, DCO-6 specifically inhibited TLR4-dependent p38 activation without directly inhibiting its kinase activity. LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex. Administering DCO-6 significantly protected mice from LPS-induced septic shock in parallel with the inhibition of p38 activation and ROS production. Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway. Blockade of the upstream events required for p38 MAPK action by DCO-6 may provide a new therapeutic option in the treatment of inflammatory diseases.

Yu Z.,Nanjing University
Zhen ci yan jiu = Acupuncture research / [Zhongguo yi xue ke xue yuan Yi xue qing bao yan jiu suo bian ji] | Year: 2013

To observe the effect of electroacupuncture (EA) stimulation of different acupoints or acupoint pairs on gastric motility so as to explore their modulation regularities under different conditions. SD rats were randomly divided into normal control, starvation (food-deprivation for 24 h), atropine (antagonist for M-receptor), acetylcholine (Ach, agonist for M-receptor), propranolol (antagonist for beta-receptor) and clenbuterol (agonist for beta 2-receptor) and paired-acupoint groups (30 rats/group). The intragastric pressure was measured via a pressure transducer connected to a balloon inserted in the stomach cavity. EA (2 Hz /15 Hz, 2 mA) was applied to the left "Tianshu" (ST 25),"Quchi" (LI 11) and "Shangjuxu" (ST 37) which were formed in pairs: ST 25-LI 11, ST 25-ST 37 and LI 11-ST 37 for 2 min following intravenous injection of atropine (0.1%, 0.8 mL/kg, 40 microL x min(-1) x kg(-1)), 0.1% acetylcholine (20 microL x min(-1) x kg(-1)), 0. 2% clenbuterol (80 microL x min(-1) x kg(-1)) and 0.4% propranolol (1 mL/kg,40 microL x min(-1) x kg(-1)) under food-deprivation conditions. After intravenous injection of atropine and clenbuterol, the intragastric pressure were decreased significantly (P < 0.05), while after administration of Ach and propranolol, the intragastric pressure increased markedly (P < 0.05). Under normal and starvation conditions, and after intravenous administration of M-receptor antagonist (atropine) and agonist (Ach), beta-receptor antagonist (propranolol) and agonist (clenbuterol), EA stimulation of ST 25 produced an apparently inhibitory effects on gastric motility (80.00%, 86.67%, 76.67%, 86.67%, 73.33% and 86.67%, respectively) and intragatric pressure (P < 0.05) with the tendency being starvation > normal, acetylcholine > atropine and clenbuterol > propranolol. Whereas EA stimulation of LI 11 and ST 37 mainly produced an excitatory effect on gastric motility (60.00%, 56.67%, 93.33%, 40.00%, 53.33% and 50.00%, respectively for LI 11; 66.67%, 60.00%, 80.00%, 53.33%, 46.67% and 73.33%, respectively for ST 37). Following EA stimulation of the paired-acupoint groups, ST 25-ST 37 induced a predominately inhibitory effect on gastric motility (50.00%) and intragastric pressure, while LI 11-ST 37 stimulation had a principally excitatory effect on gastric motility (53.33%), and ST 25-LI 11 showed no apparent effect (50.00%). EA stimulation of ST 25 area at the abdomen produces a predominant inhibitory effect on gastric motility, while EA of LI 11 and ST 37 on the upper and lower limbs induces an excitatory effect on gastric movement, when applied in pairs, EA of ST 25-ST 37 suppresses the gastric activity, and LI 11-ST 37 promotes the gastric activity, suggesting a specificity of the effect of different acupoint stimulation.

Wang X.,Nanjing University
Applied Physics Letters | Year: 2010

An acoustical theory is developed for sound transmitting through subwavelength apertures. We show that the excitation of evanescent high-order modes induces, on each end of an aperture (either a slit or a hole), an additional acoustical reactance, which is singular as incident wavelength approaches one of cutoff wavelengths of high modes. The anomaly of the induced reactance greatly changes the resonant behaviors of the aperture, and makes the conjugate impedance matching possible at a wavelength slightly longer than the cutoff, thus leading to the extraordinary full transmission. © 2010 American Institute of Physics.

Chen F.,Nanjing University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To proceed a preliminary analysis of the quality of Antrodia camphorata powder. The contents of water-soluble extract were detected according to the standards stated in Chinese Pharmacopoeia. UV-VIS was used to analyze total polysaccharide and triterpenoid. HPLC method was applied for the analysis of adenosine in Antrodia. camphorata. Besides, volatile compounds were analyzed by HSGC-MS. The contents of water-soluble extract (37.26% - 40.98%), total polysaccharide (5.45% - 8.08%), total triterpenoid (2.44% - 2.87%) and adenosine (0.0470% - 0.0604%) were obtained respectively. 49 volatile compounds were identified in Antrodia camphorata powder. The established method can be used for the quality control of Antrodia camphorata powder.

An efficient ultrasound-assisted extraction technique was employed to extract total flavonoids from Sparganii rhizoma. The optimum extraction conditions for the highest yield of total flavonoids were ethanol concentration 53.62%, ultrasonication time 29.41 min and ultrasound power 300 W, which were determined using response surface methodology. The extraction yields of the optimal ultrasound-assisted extraction were higher than using conventional extraction. The crude extract was then purified on a polyamide resin, whereby the flavonoids content in the purified extract increased to 94.62%. The antioxidant activities of the purified flavonoids including DPPH radical scavenging activity, ABTS+ radical scavenging activity, reducing power, hydroxyl radical scavenging activity and superoxide anion scavenging activity, were evaluated in vitro, which suggested that the flavonoids showed significant antioxidant activities. Rutin, kaempferol and formononetin were identified in the extract by comparing relative retention times and UV-Vis spectra with those of reference standards.

Huang H.,Nanjing Normal University | Ping J.,Nanjing Normal University | Wang F.,Nanjing University
Physical Review C - Nuclear Physics | Year: 2014

We perform a dynamical calculation of the dibaryon candidates with IJP=03+ and IJP=30+ in the framework of two constituent quark models: the quark delocalization color screening model and the chiral quark model. Our results show that the dibaryon resonances with IJP=03+ and IJP=30+ can be formed in both models. The mass and width of IJP=03+ state are smaller than that of IJP=30+ state due to the one-gluon-exchange interaction between quarks. The resonance mass and decay width of IJP=03+ state in both models agree with that of the recently observed resonance in the reaction pn 0 0. The IJP=30+ is another dibaryon candidate with smaller binding energy and larger width. The hidden-color channel coupling is added to the chiral quark model, and we find it can lower the mass of the dibaryons by 10 20 MeV. © 2014 American Physical Society.

Ma Y.,Chinese Academy of Sciences | Zhang L.,Chinese Academy of Sciences | Huang X.,Nanjing University
FEBS Journal | Year: 2014

Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas)9-mediated genome modification enables us to edit the genomes of a variety of organisms rapidly and efficiently. The advantages of the CRISPR/Cas9 system have made it an increasingly popular genetic engineering tool for biological and therapeutic applications. Moreover, CRISPR/Cas9 has been employed to recruit functional domains that repress/activate gene expression or label specific genomic loci in living cells or organisms, in order to explore developmental mechanisms, gene expression regulation, and animal behavior. One major concern about this system is its specificity; although CRISPR/Cas9-mediated off-target mutation has been broadly studied, more efforts are required to further improve the specificity of CRISPR/Cas9. We will also discuss the potential applications of CRISPR/Cas9. © 2014 FEBS.

Yang K.,Soochow University of China | Yuan B.,Soochow University of China | Ma Y.-Q.,Soochow University of China | Ma Y.-Q.,Nanjing University
Nanoscale | Year: 2013

It is increasingly recognized that the investigation of the rotational motion of geometric nanoparticles in the cellular internalization process is significant to understand certain fundamental cellular activities, such as endocytosis. However, the mechanism of rotation of geometric nanoparticles in the internalization process is still largely unknown. Here, we investigate the rotational dynamics of geometric nanoparticles when they adhere onto or are wrapped by lipid membranes, by using dissipative particle dynamics. A variety of rotational modes of the nanoparticles are observed, which are closely related to the complicated competition in the internalization process. We find that the breaking of geometric symmetry of a nanoparticle is important for the occurrence of particle rotation, while its effect can be changed by the orientation of the nanoparticles and the affinity between the ligands and the receptors. Importantly, it is found by our simulations that the rotational mode even determines the possible perturbation of the geometric nanoparticle to the membrane and the configuration between the nanoparticle and lipid membrane in the internalization process. These results provide a new strategy and also provide pivotal insight for the design of nanoparticles as advanced drug-delivery vectors to cells. © 2013 The Royal Society of Chemistry.

Lu G.M.,Nanjing University
AJR. American journal of roentgenology | Year: 2012

OBJECTIVE: The introduction of dual-energy CT (DECT) has ushered in the ability of material differentiation and tissue characterization beyond the traditional CT attenuation scale. This quality has been exploited for visualizing and quantifying the specific tissue content using radiographic contrast agents, such as iodine-based contrast media or inhaled xenon gas. Applications of this paradigm in the thorax include characterization of the pulmonary blood pool in the setting of acute or chronic pulmonary embolism (PE) and characterization of diseases of the lung parenchyma. Selective xenon detection is being explored for imaging of lung ventilation. In addition, the usefulness of DECT-based selective iodine uptake measurements has been described for the diagnosis and surveillance of thoracic malignancies. This article reviews the current applications of DECT-based imaging techniques in the chest with an emphasis on the diagnosis and characterization of pulmonary thromboembolic disorders. CONCLUSION: DECT can provide both anatomic and functional information about the lungs in a variety of pulmonary disease states based on a single contrast-enhanced CT examination. This quality has been shown to improve the diagnosis of acute and chronic PEs, other vascular disorders, lung malignancies, and parenchymal diseases. Further developments in DECT techniques and CT scanner technology will further foster and enhance the utility of this application and open new avenues in lung imaging.

Miao B.F.,Johns Hopkins University | Miao B.F.,Nanjing University | Huang S.Y.,Johns Hopkins University | Qu D.,Johns Hopkins University | Chien C.L.,Johns Hopkins University
Physical Review Letters | Year: 2014

A new type of magnetoresistance (MR) observed in Pt/YIG when nominally nonmagnetic Pt comes in contact with a ferrimagnetic insulator yttrium iron garnet (YIG) has drawn intense experimental and theoretical interest. In this Letter, we experimentally demonstrate two physical origins of the new MR: a spin current across the Pt/YIG interface and the magnetic proximity effect. The new MR can also be reproduced when Pt is in contact with a nonmagnetic insulator doped with a few percent of Fe impurities. By tuning the YIG surface and inserting an Au layer between the Pt and YIG, we are able to separate the two contributions. © 2014 American Physical Society.

Yang X.,Nanjing University | Yang X.,University of Bayreuth
Earth and Planetary Science Letters | Year: 2015

Experimental studies of OH solubility in peridotite minerals are of crucial importance for understanding some key geochemical, geophysical and geodynamical properties of the upper mantle. In reducing depths of the upper mantle, C-O-H fluids are dominated by CH4 and H2O. However, available experimental H-annealing of olivine concerning water storage capacity in the reducing upper mantle has been exclusively carried out by equilibrating olivine with H2O only. In this study, OH solubility in olivine has been investigated by annealing natural olivine crystals under peridotite-bearing and CH4-H2O-present conditions with piston cylinder and multi-anvil apparatus. Experiments were performed at 1-7 GPa and 1100-1350°C and with oxygen fugacity controlled by Fe-FeO buffer, and OH solubilities were measured from polarized infrared spectra. The olivines show no change in chemical composition during the experiments. The infrared spectra of all the annealed olivines show OH bands in the range 3650-3000 cm-1, at both high (>3450 cm-1) and low (<3450 cm-1) frequency, and the bands at ~3400-3300 cm-1 are greatly enhanced above ~3 GPa and 1300°C. The determined H2O solubility is ~90-385 ppm for the olivine coexisting with H2O (1-7 GPa and 1100°C), and is ~40-380 ppm for the olivine coexisting with CH4-H2O (1-7 GPa and 1100-1350°C). When CH4 is present in the equilibrium fluid, the H2O solubility is reduced by a factor of ~2.3 under otherwise identical conditions, indicating a strong effect of CH4 on the partitioning of water between olivine and coexisting fluid. The storage capacity of water in the reducing upper mantle is, modeled with the measured solubility of olivine and available partition coefficients of water between coexisting minerals, up to ~2 orders of magnitude lower than some previous estimates. Considering the temperature along the geotherm in the reducing oceanic upper mantle, the required H2O concentration to trigger hydrous melting is 250 and 535 ppm at ~100 and 210 km depth, respectively, and is even larger at greater depths. These values exceed the typical H2O abundance (~100±50 ppm) in the upper mantle, suggesting that pervasive hydrous melting at reducing depths of the oceanic upper mantle is not likely. Similar arguments may also be casted for the reducing deep upper mantle in the continental regions. © 2015 Elsevier B.V.

Li X.L.,Nanjing University
Zhonghua shi yan he lin chuang bing du xue za zhi = Zhonghua shiyan he linchuang bingduxue zazhi = Chinese journal of experimental and clinical virology | Year: 2012

To study the infected information, clinical symptom and molecular epidemiological characteristics of HuCV infection among children under 5 years old in Nanjing. In Nanjing Children's Hospital of Nanjing Medical University from July 2010 to June 2011, we collected 428 stool specimens from children with diarrhea and 428 asymptomatic controls. Human Calicivirus were tested by using RT-PCR. Then we sequenced the nucleic acid of PCR amplifications and identified the genotype and gene group of prevalent strains. 63 (14.72%) out of 428 stool samples were detected as HuCV. 58 were norovirus and 5 were sapovirus, while GII-4 2006b was the predominant strain of NoV. In the 428 control samples, 19 samples were positive for calicivirus, there were 8 NoV and 13 SaV (Including 3 co-infection cases). Human caliciviruses with different genotypes circulated among children in Nanjing,and GII. 2006b is the dominant genotype.

Nisar N.,Australian National University | Li L.,Cornell University | Lu S.,Nanjing University | Khin N.C.,Australian National University | Pogson B.J.,Australian National University
Molecular Plant | Year: 2015

Carotenoids are mostly C40 terpenoids, a class of hydrocarbons that participate in various biological processes in plants, such as photosynthesis, photomorphogenesis, photoprotection, and development. Carotenoids also serve as precursors for two plant hormones and a diverse set of apocarotenoids. They are colorants and critical components of the human diet as antioxidants and provitamin A. In this review, we summarize current knowledge of the genes and enzymes involved in carotenoid metabolism and describe recent progress in understanding the regulatory mechanisms underlying carotenoid accumulation. The importance of the specific location of carotenoid enzyme metabolons and plastid types as well as of carotenoid-derived signals is discussed. © 2015 The Author.

Xiao M.,Nanjing University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2011

To investigate the chemical constituents in the leaves of Lindera aggregate. Compounds were separated by column chromatography with silica gel and ODS. The structures were identified by physicochemical properties and spectral analysis (1H-NMR, 13C-NMR). Eight compounds were isolated and identified as: quercetin-3-O-L-rhamnoside(1), kaempferol-3-O-L-rhamnoside(2), kaempferol(3), dihydrokaempferol-3-O-L-rhamnoside (4), quercetin (5), quercetin-3-O-alpha-D-arabinofuranoside (6), quercetin-3-O-alpha-D-glucopyranoside(7), kaempferol-3-O-D-glucopyranoside(8). Compounds 2,4 and 8 are obtained from Lindera aggregata for the first time.

Bao M.,Nanjing University | Hartmann D.L.,University of Washington
Geophysical Research Letters | Year: 2014

This study examines the response to Madden-Julian Oscillation (MJO)-like heat forcing in a nonlinear shallow-water model, including monopolar heating source traveling eastward with an around the world period of 48 days and dipolar heating with zonal wave period of 48 days, with zonal wave number 2 confined in longitude to the MJO active regions. A jet localized in the Pacific is compared to a zonally uniform boreal basic flow. The results show that the Rossby wave response downstream exhibits intensified quasi-stationary anomalies in the Pacific jet exit region when the MJO-like heat forcing passes the Maritime Continent, in accord with the observational analysis by Adames and Wallace (2014). The dynamical mechanism suggested in this study can be used to interpret the intraseasonal MJO-Pacific North American pattern coherence and other extratropical intraseasonal events. Key Points Response to MJO-like forcing is simulated in a nonlinear shallow-water model Strong quasi-stationary Rossby wave response in the Pacific jet exit region Extraction of kinetic energy from the mean flow in the jet exit region is vital ©2014. American Geophysical Union. All Rights Reserved.

Liu L.,University of Wisconsin - Milwaukee | Gao F.,Nanjing University | Zhao H.,University of Wisconsin - Milwaukee | Li Y.,University of Wisconsin - Milwaukee
Applied Catalysis B: Environmental | Year: 2013

The incorporation of Cu species in TiO2 photocatalysts is critical in photocatalytic CO2 reduction to fuels, but the effect of Cu valence is poorly understood. In this work, Cu/TiO2 (P25) nanoparticle catalysts were prepared by a simple precipitation and calcination method. The as-prepared Cu/TiO2 sample was dominated by Cu2+ species. Thermal pretreatment of the as-prepared samples in He and H2 atmosphere resulted in the transition to a surface dominated by Cu+ and mixed Cu+/Cu0, respectively, confirmed by in situ X-ray photoelectron spectroscopy (XPS) and diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses. These thermal pretreatments in reducing atmospheres also induced the formation of defect sites such as oxygen vacancies and Ti3+. The various Cu/TiO2 catalysts were tested in CO2 photoreduction with water vapor under simulated solar irradiation, and their activities were in the order of as-prepared (unpretreated)

Zhao Y.,Nanjing University | Zhang J.,Jiangsu Academy of Environmental Sciences | Nielsen C.P.,Harvard University
Atmospheric Chemistry and Physics | Year: 2014

To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total suspended particles (TSP), PM10, and PM2.5 are estimated to decline 7, 20, 41, 34, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17 (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12 and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby concentrations of negative-forcing sulfate particles. Expanded control of emissions of fine particles and carbonaceous aerosols from small industrial and residential sources is recommended, and a more comprehensive emission control strategy targeting a wider range of pollutants (volatile organic compounds, NH3 and CO, etc.) and taking account of more diverse environmental impacts is also urgently needed. © 2014 Author(s).

Li G.,Nanjing University | West A.J.,University of Southern California
Earth and Planetary Science Letters | Year: 2014

The Li isotopic record of seawater shows a dramatic increase of ~9s over the past ~60 million years. Here we use a model to explore what may have caused this change. We focus particularly on considering how changes in the "reverse weathering" sinks that remove Li from seawater can contribute to explain the observed increase. Our interpretation is based on dividing the oceanic sink, which preferentially removes light Li, into two components: (i) removal into marine authigenic clays in sediments at low temperatures, with associated high fractionation factors, and (ii) removal into altered oceanic basalt at higher temperatures and resulting lower fractionation factors. We suggest that increases in the flux of degraded continental material delivered to the oceans over the past 60 Ma could have increased removal of Li into sedimentary authigenic clays versus altered basalt. Because altered basalt is associated with a smaller isotopic fractionation, an increasing portion of the lower temperature (authigenic clay-associated) sink could contribute to the rise of the seawater Li isotope value. This effect would moderate the extent to which the isotopic value of continental inputs must have changed in order to explain the seawater record over the Cenozoic. Nonetheless, unless the magnitude of fractionation during removal differs significantly from current understanding, substantial change in the δLi7 of inputs from continental weathering must have occurred. Our modeling suggests that dissolved riverine fluxes in the early Eocene were characterized by δLi7 of ~0 to +13‰, with best estimates of 6.6-12.6‰; these values imply increases over the past 60 Myrs of between 10 and 24‰, and we view a ~13‰ increase as a likely scenario. These changes would have been accompanied by increases in both the dissolved Li flux from continental weathering and the removal flux from seawater into marine authigenic clays. Increases in δLi7 of continental input are consistent with a change in the global denudation regime as a result of increasing continental erosion rate through the Cenozoic. Changes in denudation may have meant increasing climate sensitivity of weathering over time but do not require globally supply-limited and thus entirely climate-insensitive weathering in the early Cenozoic. © 2014 Elsevier B.V.

Li C.,Nanjing University | Li C.,Yunnan University | Brandenberger R.H.,McGill University | Cheung Y.-K.E.,McGill University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We report on the possibility of using dark matter particle's mass and its interaction cross section as a smoking gun signal of the existence of a big bounce at the early stage in the evolution of our currently observed universe. A model independent study of dark matter production in the pre-bounce contraction and the post-bounce expansion epochs of the bounce universe reveals a new venue for achieving the observed relic abundance of our present universe, in which a significantly smaller amount of dark matter with a smaller cross section - as compared to the prediction of standard cosmology - is produced and the information about the bounce universe evolution is preserved by the out-of-thermal-equilibrium process. Once the value of dark matter mass and interaction cross section are obtained by direct detection in laboratories, this alternative route becomes a signature prediction of the bounce universe scenario. © 2014 American Physical Society.

Wang X.,Nanjing University | Power P.P.,University of California at Davis
Angewandte Chemie - International Edition | Year: 2011

O/N-H•••π hydrogen bonds: Water-benzene and ammonia-benzene complexes are stabilized by the Lewis acid B(C 6F 5) 3 and provide rare structural (X-ray) and infrared spectroscopic data for water-benzene and ammonia-benzene complexes in the solid state (see picture). The infrared spectra of the complexes showed that the O-H and N-H stretching frequencies decrease significantly on benzene complexation. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The ion solvation in aqueous solution under different temperatures and pressures governs many important biological, geological, and chemical processes. In this work, we present a theoretical study of hydration structures of several alkali metal cations and halide anions, Na+, K+, F -, and Cl-, in ambient and supercritical water through quantum mechanics/molecular mechanics (QM/MM) simulations. It is shown that our calculated first peak or minimum positions for the radial distribution functions of ion-water pairs and hydration numbers Nhydration as well as hydrogen bond numbers NHB are in good agreements with available experimental determinations or other high-level QM/MM simulated results. We reveal that Nhydration under supercritical condition does not reduce much comparing to that under ambient condition due to the inherent local clustering effect although the bulk density decreases evidently. After the investigation of the angular distribution of oxygen-ion-oxygen within the first hydration sphere, it is shown that Na + or F- in ambient water tends to be six-fold coordinated in a octahedral-like structure. Through the analysis of ion-oxygen-hydrogen angle distributions within the first hydration spheres of F- and Cl-, we also find that strong hydrogen bonds exist in ambient aqueous F- and become weakened under supercritical condition, whereas weak hydrogen bonds exist in ambient aqueous Cl- and become nearly disappeared under supercritical condition. © 2013 Wiley Periodicals, Inc.

Deng S.,Nanjing University
The Analyst | Year: 2013

Since the electrogenerated chemiluminescence (ECL) of silicon nanoparticles (NPs) was reported in 2002, miscellaneous nanomaterials with various sizes and shapes have been employed as ECL nanoemitters for bioanalysis. Elucidation of the ECL derivation from these nanoemitters and pertinent biofunctionalization with multitudinous biomolecules can offer excellent ECL signal-transduction platforms for fabricating novel biosensing devices. In this review, we comprehensively describe retrospective and recent advances in NPs-based ECL and related biosensing methodologies, and review their analytical applications in the detection of small biological molecules, enzymatic sensing, immunoassay, DNA analysis and cytosensing.

Cao Y.,University of British Columbia | Cao Y.,Nanjing University | Li H.,University of British Columbia
Biophysical Journal | Year: 2011

Many proteins in living cells require cofactors to carry out their biological functions. To reach their functional states, these proteins need to fold into their unique three-dimensional structures in the presence of their cofactors. Two processes, folding of the protein and binding of cofactors, intermingle with each other, making the direct elucidation of the folding mechanism of proteins in the presence of cofactors challenging. Here we use single-molecule atomic force microscopy to directly monitor the folding and cofactor binding dynamics of an engineered metal-binding protein G6-53 at the single-molecule level. Using the mechanical stability of different conformers of G6-53 as sensitive probes, we directly identified different G6-53 conformers (unfolded, apo- and Ni 2+-bound) populated along the folding pathway of G6-53 in the presence of its cofactor Ni 2+. By carrying out single-molecule atomic force microscopy refolding experiments, we monitored kinetic evolution processes of these different conformers. Our results suggested that the majority of G6-53 folds through a binding-after-folding mechanism, whereas a small fraction follows a binding-before-folding pathway. Our study opens an avenue to utilizing force spectroscopy techniques to probe the folding dynamics of proteins in the presence of cofactors at the single-molecule level, and we anticipated that this method can be used to study a wide variety of proteins requiring cofactors for their function. © 2011 Biophysical Society.

Corpman D.W.,Nanjing University
Journal of Health Communication | Year: 2013

There are nearly 1 billion mobile phone subscribers in China. Health care providers, telecommunications companies, technology firms, and Chinese governmental organizations use existing mobile technology and social networks to improve patient-provider communication, promote health education and awareness, add efficiency to administrative practices, and enhance public health campaigns. This review of mobile health in China summarizes existing clinical research and public health text messaging campaigns while highlighting potential future areas of research and program implementation. Databases and search engines served as the primary means of gathering relevant resources. Included material largely consists of scientific articles and official reports that met predefined inclusion criteria. This review includes 10 reports of controlled studies that assessed the use of mobile technology in health care settings and 17 official reports of public health awareness campaigns that used text messaging. All source material was published between 2006 and 2011. The controlled studies suggested that mobile technology interventions significantly improved an array of health care outcomes. However, additional efforts are needed to refine mobile health research and better understand the applicability of mobile technology in China's health care settings. A vast potential exists for the expansion of mobile health in China, especially as costs decrease and increasingly sophisticated technology becomes more widespread. © 2013 Copyright Taylor and Francis Group, LLC.

Jiang P.,Anhui University of Science and Technology | Jiang P.,University of Pennsylvania | Du W.,Anhui University of Science and Technology | Du W.,University of Pennsylvania | And 5 more authors.
Nature Cell Biology | Year: 2011

Cancer cells consume large quantities of glucose and primarily use glycolysis for ATP production, even in the presence of adequate oxygen. This metabolic signature (aerobic glycolysis or the Warburg effect) enables cancer cells to direct glucose to biosynthesis, supporting their rapid growth and proliferation. However, both causes of the Warburg effect and its connection to biosynthesis are not well understood. Here we show that the tumour suppressor p53, the most frequently mutated gene in human tumours, inhibits the pentose phosphate pathway (PPP). Through the PPP, p53 suppresses glucose consumption, NADPH production and biosynthesis. The p53 protein binds to glucose-6-phosphate dehydrogenase (G6PD), the first and rate-limiting enzyme of the PPP, and prevents the formation of the active dimer. Tumour-associated p53 mutants lack the G6PD-inhibitory activity. Therefore, enhanced PPP glucose flux due to p53 inactivation may increase glucose consumption and direct glucose towards biosynthesis in tumour cells. © 2011 Macmillan Publishers Limited. All rights reserved.

Yan D.,Beijing University of Chemical Technology | Lu J.,Beijing University of Chemical Technology | Ma J.,Nanjing University | Wei M.,Beijing University of Chemical Technology | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Thermochromic luminescence is characteristic of the title system, which is fabricated by layer-by-layer assembly of anionic bis(2-sulfonatostyryl)biphenyl (BSB) and positively charged layered double hydroxide (LDH) nanosheets on quartz glass. The BSB/LDH films show fast luminescent response and switching properties, including changes in color (see picture), fluorescence lifetime, and anisotropy in the range 20-100 °C. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang M.-L.,Nanjing Southeast University | Zhang M.-L.,Nanjing University
IJCAI International Joint Conference on Artificial Intelligence | Year: 2011

Multi-label learning deals with the problem where each training example is represented by a single instance while associated with a set of class labels. For an unseen example, existing approaches choose to determine the membership of each possible class label to it based on identical feature set, i.e. the very instance representation of the unseen example is employed in the discrimination processes of all labels. However, this commonly-used strategy might be suboptimal as different class labels usually carry specific characteristics of their own, and it could be beneficial to exploit different feature sets for the discrimination of different labels. Based on the above reflection, we propose a new strategy to multi-label learning by leveraging label-specific features, where a simple yet effective algorithm named LIFT is presented. Briefly, LIFT constructs features specific to each label by conducting clustering analysis on its positive and negative instances, and then performs training and testing by querying the clustering results. Extensive experiments across sixteen diversified data sets clearly validate the superiority of LIFT against other well-established multi-label learning algorithms.

Boronate affinity functionalized materials have recently drawn increasing attention due to their capability to selectively isolate and enrich glycoproteins and glycopeptides. As cheaper and more stable competitors to lectins, boronic acids are generally believed to yield a relatively wider spectrum specificity to glycoproteins. For better understanding and effective utilization of boronate affinity, it is necessary to establish if boronic acids exhibit lectin-like narrow specificity towards individual or a sub-class of glycoproteins. Here we report a pH manipulation strategy for fine-tuning the specificity of boronate affinity monoliths towards two sub-classes of glycoproteins, sialylated and nonsialylated glycoproteins. When the binding pH > the pK(a) of the boronic acid by one pH unit or more, the boronate affinity monolith preferentially binds to glycoproteins containing neutral sugars and excludes sialic acid containing glycoproteins due to electrostatic repulsion. When the binding pH < the pK(a) by one pH unit or more, the boronate affinity monolith binds to sialylated glycoproteins due to the exceptional binding affinity of the boronic acid towards sialic acid residues. The alternative specificity towards sialic acid and neutral sugar was first verified using an off-line combination of boronate affinity extraction with nano-ESI-Orbitrap MS/MS detection. The alternative specificity towards sialylated and nonsialylated glycoproteins was then demonstrated by means of off-line combination of boronate affinity extraction with MALDI-TOF MS. Finally, the developed approach was applied to the alternative extraction of intact sialylated and nonsialylated glycoproteins spiked in human serum.

Nellist P.D.,University of Oxford | Wang P.,Nanjing University
Annual Review of Materials Research | Year: 2012

Aberration correction in the transmission electron microscope has led to a reduction in the depth of focus for imaging. The depth of focus in a state-of-the-art scanning transmission electron microscope system, which is currently just a few nanometers, creates an opportunity to explore the three-dimensional structure of a sample by focusing on specific layers, an approach known as optical sectioning. In this article, we review the performance of optical sectioning in the scanning transmission electron microscope. Limitations in the simple optical sectioning approach are used to motivate discussion of confocal electron microscopy. Three imaging modes in scanning confocal electron microscopy have been investigated both theoretically and experimentally, and are reviewed here. The method of implementing a confocal arrangement in a microscope is discussed, along with its comparative performance with other methods for three-dimensional imaging and analysis. Finally, current and future potential applications are discussed. © Copyright ©2012 by Annual Reviews. All rights reserved.

A new method for the synthesis of β-N-(γ-L(+)-glutamyl)phenylhydrazine is presented. This compound was prepared from L-glutamine and phenylhydrazine through a transpeptidation reaction of Escherichia coli γ-glutamyltranspeptidase although phenylhydrazine has been reported to be an inhibitor of the enzyme. The optimum reaction conditions were 60 mM L-glutamine, 300 mM phenylhydrazine, 40 U γ-glutamyltranspeptidase/ml, and pH 9 in approx. 800 ml. After 6 h at 37 °C, the product was obtained with a conversion rate of 93 % (mol/mol). γ-Glutamyltranspeptidase was reversibly inhibited only when phenylhydrazine was above 300 mM.

Tian J.,Nanjing University
Cancer Research and Clinic | Year: 2014

Neoadjuvant radiotherapy could decrease the local recurrence rate, increase the probability of the anal sphincter preservation, improve survival rate and the quality of patients' lives. For stage III patients with rectal cancer, the recurrence rate is higher in short-course radiotherapy compared with conventionally radiotherapy. Molecular markers combined with gene technology can be used as radiosensitivity indicators. Conventional radiotherapy has a definite effect and radiotherapy combined with chemotherapy has better efficacy. The extensive researches of diverse molecular markers,gene expression profiling and gene chips for rectal cancer provide the basis of personalized treatment.

We previously found that the low frequency magnetic fields (LF-MF) inhibited gastric and lung cancer cell growth. We suppose that exposure to LF-MF may modulate immune function so as to inhibit tumor. We here investigated whether LF-MF can inhibit the proliferation and metastasis of melanoma and influence immune function. The effect of MF on the proliferation, cell cycle and ultrastracture of B16-F10 in vitro was detected by cell counting Kit-8 assay, flow cytometry, and transmission electron microscopy. Lung metastasis mice were prepared by injection of 2 × 105 B16-F10 melanoma cells into the tail vein in C57BL/6 mice. The mice were then exposed to an LF-MF (0.4 T, 7.5 Hz) for 43 days. Survival rate, tumor markers and the innate and adaptive immune parameters were measured. The growth of B16-F10 cells was inhibited after exposure to the LF-MF. The inhibition was related to induction of cell cycle arrest and decomposition of chromatins. Moreover, the LF-MF prolonged the mouse survival rate and inhibited the proliferation of B16-F10 in melanoma metastasis mice model. Furthermore, the LF-MF modulated the immune response via regulation of immune cells and cytokine production. In addition, the number of Treg cells was decreased in mice with the LF-MF exposure, while the numbers of T cells as well as dendritic cells were significantly increased. LF-MF inhibited the growth and metastasis of melanoma cancer cells and improved immune function of tumor-bearing mice. This suggests that the inhibition may be attributed to modulation of LF-MF on immune function and LF-MF may be a potential therapy for treatment of melanoma.

Four-wave-mixing (FWM) acts as noise due to randomness of bit sequences of all channels for wavelength-division-multiplexed (DWDM) system. The approximate direct ratios of variances of FWM noise between two cases are obtained. One of them, we call "CASE A", is that the input polarization states of all channels are independently random and birefringence strength and orientation along fiber vary randomly. The other, called "CASE B", is the input polarizations of all channels are same and birefringence along the whole fiber line does not exist. Including randomness of bit sequences and walk-off between channels, for intensity-modulated/direct-detection (IM/DD) dispersion-managed (DM) DWDM system, the performance degradation due to FWM effect is calculated for "CASE A". The calculation model is based on the direct ratios between the above-mentioned two cases derived in this paper and a semi-analytic approach for "CASE B" having been introduced in previous works. The calculative results provide optimized dispersion maps used to reduce the FWM noise. In order to reduce the overall FWM noise from all channel combinations, when polarization controllers are adopted at transmitters, the launched polarizations between neighboring channels are suggested to have appropriately larger degrees of orthogonality than non-neighboring channels. © 2012 Elsevier Inc. All rights reserved.

The stochastic resonance algorithm (SRA) has been developed as a potential tool for amplifying and determining weak chromatographic peaks in recent years. However, the conventional SRA cannot be applied directly to ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOFMS). The obstacle lies in the fact that the narrow peaks generated by UPLC contain high-frequency components which fall beyond the restrictions of the theory of stochastic resonance. Although there already exists an algorithm that allows a high-frequency weak signal to be detected, the sampling frequency of TOFMS is not fast enough to meet the requirement of the algorithm. Another problem is the depression of the weak peak of the compound with low concentration or weak detection response, which prevents the simultaneous determination of multi-component UPLC/TOFMS peaks. In order to lower the frequencies of the peaks, an interpolation and re-scaling frequency stochastic resonance (IRSR) is proposed, which re-scales the peak frequencies via linear interpolating sample points numerically. The re-scaled UPLC/TOFMS peaks could then be amplified significantly. By introducing an external energy field upon the UPLC/TOFMS signals, the method of energy gain was developed to simultaneously amplify and determine weak peaks from multi-components. Subsequently, a multi-component stochastic resonance algorithm was constructed for the simultaneous quantitative determination of multiple weak UPLC/TOFMS peaks based on the two methods. The optimization of parameters was discussed in detail with simulated data sets, and the applicability of the algorithm was evaluated by quantitative analysis of three alkaloids in human plasma using UPLC/TOFMS. The new algorithm behaved well in the improvement of signal-to-noise (S/N) compared to several normally used peak enhancement methods, including the Savitzky-Golay filter, Whittaker-Eilers smoother and matched filtration. Copyright © 2011 John Wiley & Sons, Ltd.

Li B.,Nanjing Southeast University | Xing Z.W.,Nanjing University | Liu M.,Nanjing Southeast University
Applied Physics Letters | Year: 2011

Using first-principles calculations in a supercell model with structural optimization, we investigate the magnetic ground state of LiFeAs and its phonon spectrum. The obtained magnetic ground state is the marginal striped antiferromagnetic state with partial structural relaxations. It is found that the anisotropic spin-lattice coupling in LiFeAs results in phonon softening of Fe-As atomic motion and so enhances the electron-phonon coupling. As a result, the electron-phonon interactions through the spin channel play an important role in the superconductivity of LiFeAs. © 2011 American Institute of Physics.

Wu Q.,Nanjing University | zhang X.,University of Alaska Fairbanks
Journal of Climate | Year: 2011

A lagged maximum covariance analysis (MCA) is applied to investigate the linear covariability between monthly sea ice concentration (SIC) and 500-mb geopotential height (Z500) in the Southern Hemisphere (SH). The dominant signal is the atmospheric forcing of SIC anomalies throughout the year, but statistically significant covariances are also found between austral springtime Z500 and prior SIC anomalies up to four months earlier. The MCA pattern is characterized by an Antarctic dipole (ADP)-like pattern in SIC and a positively polarized Antarctic Oscillation (AAO) in Z500. Such long lead-time covariance suggests the forcing of the AAO by persistent ADP-like SIC anomalies. The leading time of SIC anomalies provides an implication for skillful predictability of springtime atmospheric variability. © 2011 American Meteorological Society.

Chen P.F.,Nanjing University
Living Reviews in Solar Physics | Year: 2011

Coronal mass ejections (CMEs) are the largest-scale eruptive phenomenon in the solar system, expanding from active region-sized nonpotential magnetic structure to a much larger size. The bulk of plasma with a mass of ~ 1011 - 1013 kg is hauled up all the way out to the interplanetary space with a typical velocity of several hundred or even more than 1000 km s-1, with a chance to impact our Earth, resulting in hazardous space weather conditions. They involve many other much smaller-sized solar eruptive phenomena, such as X-ray sigmoids, filament/prominence eruptions, solar flares, plasma heating and radiation, particle acceleration, EIT waves, EUV dimmings, Moreton waves, solar radio bursts, and so on. It is believed that, by shedding the accumulating magnetic energy and helicity, they complete the last link in the chain of the cycling of the solar magnetic field. In this review, I try to explicate our understanding on each stage of the fantastic phenomenon, including their pre-eruption structure, their triggering mechanisms and the precursors indicating the initiation process, their acceleration and propagation. Particular attention is paid to clarify some hot debates, e.g., whether magnetic reconnection is necessary for the eruption, whether there are two types of CMEs, how the CME frontal loop is formed, and whether halo CMEs are special.

Song Y.-Y.,Northeastern University China | Gao Z.-D.,Northeastern University China | Wang J.-H.,Northeastern University China | Xia X.-H.,Nanjing University | Lynch R.,University of Limerick
Advanced Functional Materials | Year: 2011

WO3 nanoparticles loaded in TiO2 nanotube arrays, fabricated by a chemical bath deposition (CBD) technique in combination with a pyrolysis process, is uniform and the diameter can be easily adjusted by the deposition times. The resultant hybrid nanotubes array shows a multistage coloring electrochromic response at different potential bias. The formation of a 3-dimensional WO3/TiO2 junction promotes unidirectional charge transport due to the one-dimensional features of the tubes, which leads to the significant positive-shift onset potential of the cathodic reaction (ion insertion) and the highly increased proton storage capacity. Compared to non-decorated nanotube arrays, the enhanced electrochromic properties of longer lifetime, higher contrast ratio (bleaching time/coloration time), and improved tailored electrochromic behavior could be achieved using the composite films. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cui X.,Nanjing University | Cui X.,University of California at Riverside | Mayer P.,University of Aarhus | Gan J.,University of California at Riverside
Environmental Pollution | Year: 2013

Many important environmental contaminants are hydrophobic organic contaminants (HOCs), which include PCBs, PAHs, PBDEs, DDT and other chlorinated insecticides, among others. Owing to their strong hydrophobicity, HOCs have their final destination in soil or sediment, where their ecotoxicological effects are closely regulated by sorption and thus bioavailability. The last two decades have seen a dramatic increase in research efforts in developing and applying partitioning based methods and biomimetic extractions for measuring HOC bioavailability. However, the many variations of both analytical methods and associated measurement endpoints are often a source of confusion for users. In this review, we distinguish the most commonly used analytical approaches based on their measurement objectives, and illustrate their practical operational steps, strengths and limitations using simple flowcharts. This review may serve as guidance for new users on the selection and use of established methods, and a reference for experienced investigators to identify potential topics for further research. © 2012 Published by Elsevier Ltd.

Yan G.,Suzhou College | Xuan H.,Nanjing University
Applied Physics Letters | Year: 2011

Co-doped ZnO and CoO were prepared at 950 C by the solid-state reaction method, then were annealed in N2 flow at 950 C, and finally annealed in Zn vapor at 600 C or 800 C. The samples before annealing in Zn vapor have no ferromagnetism, but after annealing in Zn vapor, Co-doped ZnO and CoO both exhibit roomerature ferromagnetism. Through x-ray diffraction and element composition measurements, it was found that the ferromagnetism of Co-doped ZnO annealed in Zn vapor is extrinsic and comes from cubic Co5Zn 21 and/or cubic CoZn. © 2011 American Institute of Physics.

Gu H.,Nanjing University
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2011

To investigate the effect of 5-hydroxymethyl furfural (5-HMF) on apoptosis and BCL-2, NF-kappaB gene expression of rat hippocampal neurons injured by hydroperoxide (H2O2). Hippocampal neurons of newly born rat were cultured in vivo and injured by H2O2. Effect of different concentration of 5-HMF on cell viability was measured by MTT. Flow cytometer (FCM) was used to measure the apoptosis of rat hippocampal neurons pre-cultured with different concentration of 5-HMF,Western blotting was used to measure the expression of BCL-2 and NF-kappaB gene. It revealed that the high and medium dosage of 5-HMF could increase the activity of rat hippocampal. The high, medium and low dosage of 5-HMF also increased the expression of BCL-2 gene and decreased the expression of NF-kappaB gene. 5-HMF could restrain the apoptosis of cultured hippocampal neurons injured by H2O2. The mechanism may be related to increasing in BCL-2 level and decreasing in NF-kappaB level.

Dai Z.,Nanjing Normal University | Ju H.,Nanjing University
TrAC - Trends in Analytical Chemistry | Year: 2012

Nanoporous materials possess nanometer-sized pore distribution and are widely used in biosensing. The unique properties of nanoporous materials include large surface area, good chemical, thermal and mechanical stability, very uniform pore distribution with tunable pore size, high adsorption capacity, and an ordered porous network for free diffusion of substrates and reaction products.Usage of nanoporous materials can significantly improve the analytical performance of biosensors in biomedical diagnosis and monitoring of food and environmental quality.This article reviews some major advances in bioanalysis based on nanoporous materials, including biosensing based on zeolite, mesoporous silica, mesoporous carbon, mesoporous metal and metal oxide. These nanoporous materials have shown promising applications in electrochemical biosensing, electrocatalysis, proteomics analysis and biorecognition. © 2012 Elsevier Ltd.

Wu J.-P.,Beijing Normal University | Zeng H.-B.,Nanjing University
Journal of High Energy Physics | Year: 2012

We report a dynamical formation of a (Mott) gap from holographic fermions. By coupling a fermion field with dipole action to the charged dilaton black branes with aLifshitz like IR geometry and AdS4 boundary, we find that when the dipole interaction is large enough, spectral weight is transferred between bands, and beyond a critical dipole interaction, a gap emerges in the fermion density of states. The value of the gap becomes larger as the strength of the interaction keeps increasing.© SISSA 2012.

Li W.X.,Nanjing University
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica | Year: 2012

To evaluate the effect of danggui-chuanxiong herb pair with different prescription proportions and formulas on nourishing and tonifying blood (NTB), activating blood circulation and dissolving blood stasis (ADBS), regulating menstruation and relieving pain (RMRP) in an all-round way, in order to reveal the correlation between the effect and constituents and their degrees. First, the indexes of effect were standardized. All effects were integrated by using multi-index aggregative index method. The weight coefficients of each index were worked out by the combining the statistics of testing frequency of each effect index given by the specialist-scored method and in relevant literatures released in the latest 10 years. Then, the total effect values were obtained by multiplying the standardized value of each index with the weight coefficients and then adding their results together. Finally, a fitting analysis was made on the contents of seven major active components in danggui-chuanxiong herb pair, total aromatic acids and total phthalide lactones and their total effect by using the artificial neural network, respectively. Water extracts of danggui-chuanxiong (1.5:1) had the best effect on total NTB; alcohol extracts of danggui-chuanxiong herb pair (1:1) had the best effect on total ADBS; alcohol extraction of danggui-chuanxiong herb pair (1.5:1) had the best effect on RMRP. By using the same extraction method, extracts of danggui had better effect on total NTB than Chuanxiong; while extracts of chuanxiong had better effect on total ADBS and RMRP than danggui. With the same prescription proportion, water extracts of danggui-chuanxiong herb pair had the best effect on total NTB; alcohol extracts of danggui-chuanxiong herb pair had the best effect on total ADBS and RMRP. Aromatic acids were the main effective components for NTB, especially chlorogenic acid and caffeic acid. Both aromatic acids and phthalide lactones were active components for ADBS, particular chlorogenic acid and senkyunolides I and H showed greater effect on ADBS. Both aromatic acids and phthalide lactones were also the important active constituents for the effect of RMRP, especially ligustilide, caffeic acid, ferulic acid, and senkyunolide I showed greater effect on RMRP. Both aromatic acids and phthalide lactones of danggui-chuanxiong herb pair contributed to NTB, ADBS and RMRP. Aromatic acids laid particular stress on NTB and ADBS, while phthalide lactones laid particular stress on RMRP. In this study, determined effect indexes of the herbal medicines were integrated by using multi-index aggregative index method, and a fitting correlation analysis was made on the component content of the herbal medicines and their integration effect by using the artificial neural network, in order to specify the active constituents of the herbal medicines with different effects and their contributions to the general efficacy and provide new ideas and methods for basic study on complicated active constituents of the herbs medicines.

Li W.,Nanjing University | Spong M.W.,University of Texas at Dallas
IEEE Transactions on Automatic Control | Year: 2014

In this technical note, we consider the cooperative control of multiple agents on a sphere, provide the appropriate attraction-repulsion interactions between agents with introduction of the state-dependent repulsive coefficients, and design the unified control laws for agents to achieve three fundamental spherical configurations or patterns: rendezvous, uniform deployment, and formation, using both the first-and second-order models. We present the analysis of the stability, scaling and geometric patterns of the models on the sphere under different attraction-repulsion parameters, with illustration of the geometrical patterns and the geometrical isomerism by simulations. The closed-loop dynamics of agents are invariant with respect to group rotation actions on the sphere. © 1963-2012 IEEE.

Wu X.,Indiana University - Purdue University Indianapolis | Zhao Y.,Indiana University - Purdue University Indianapolis | Zhang G.,Indiana University - Purdue University Indianapolis | Zhang G.,Nanjing University | Ge H.,Indiana University - Purdue University Indianapolis
Angewandte Chemie - International Edition | Year: 2014

The intramolecular dehydrogenative amidation of aliphatic amides, directed by a bidentate ligand, was developed using a copper-catalyzed sp3 C-H bond functionalization process. The reaction favors predominantly the C-H bonds of β-methyl groups over the unactivated methylene C-H bonds. Moreover, a preference for activating sp3 C-H bonds of β-methyl groups, via a five-membered ring intermediate, over the aromatic sp2 C-H bonds was also observed in the cyclometalation step. Additionally, sp3 C-H bonds of unactivated secondary sp3 C-H bonds could be functionalized by favoring the ring carbon atoms over the linear carbon atoms. Getting ahead on tams: The intramolecular dehydrogenative amidation of aliphatic amides, directed by a bidentate ligand, was developed using a copper-catalyzed sp 3 C-H bond functionalization process to deliver β-lactams. The reaction favors the C-H bonds of β-methyl groups over the unactivated methylene C-H bonds, as well as aromatic C(sp2)-H bonds and unactivated secondary C(sp3)-H bonds of rings. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lu H.,University of South Florida | Lu H.,Nanjing University | Li C.,University of South Florida | Jiang H.,University of South Florida | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

Highly chemoselective intramolecular amination of propargylic C(sp 3)-H bonds has been demonstrated for N-bishomopropargylic sulfamoyl azides through cobalt(II)-based metalloradical catalysis. Supported by D 2h-symmetric amidoporphyrin ligand 3,5-DitBu-IbuPhyrin, the cobalt(II)-catalyzed C-H amination proceeds effectively under neutral and nonoxidative conditions without the need of any additives, and generates N 2 as the only byproduct. The metalloradical amination is suitable for both secondary and tertiary propargylic C-H substrates with an unusually high degree of functional-group tolerance, thus providing a direct method for high-yielding synthesis of functionalized propargylamine derivatives. Make a ring of it: Highly chemoselective intramolecular amination of propargylic C(sp3)-H bonds has been achieved with a high degree of functional-group tolerance through the title reaction. The [Co(P1)]-catalyzed C-H amination proceeds under neutral and nonoxidative conditions without the need of any additives, thus providing a direct method for efficient synthesis of functionalized propargylamine derivatives with N2 as the only by-product. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dong L.,Nanjing University | Wang C.,University of Macau
Trends in Biotechnology | Year: 2013

Bone tissue engineering has attracted considerable attention as a promising treatment modality for severe bone degeneration. The pressing need for more sophisticated and fully functional bone substitutes has spurred a refocus on the development of bone constructs in a way more comparable to the physiological process. Current research is increasingly revealing the central roles of macrophages/monocytes in regulating bone development and repair, so we propose that these immunocytes can play a similar pivotal role in directing engineered bone regeneration. Accordingly, we discuss two possible strategies to exemplify how the distinctive power of macrophages/monocytes - particularly their cytokine-secretion ability and chemotactic response to foreign materials - can be harnessed to enhance the performance of bone tissue engineering applications. © 2013 Elsevier Ltd.

Nie C.,Nanjing University | Leung H.,Hong Kong Polytechnic University
ACM Computing Surveys | Year: 2011

Combinatorial Testing (CT) can detect failures triggered by interactions of parameters in the Software Under Test (SUT) with a covering array test suite generated by some sampling mechanisms. It has been an active field of research in the last twenty years. This article aims to review previous work on CT, highlights the evolution of CT, and identifies important issues, methods, and applications of CT, with the goal of supporting and directing future practice and research in this area. First, we present the basic concepts and notations of CT. Second, we classify the research on CT into the following categories: modeling for CT, test suite generation, constraints, failure diagnosis, prioritization, metric, evaluation, testing procedure and the application of CT. For each of the categories, we survey the motivation, key issues, solutions, and the current state of research. Then, we review the contribution from different research groups, and present the growing trend of CT research. Finally, we recommend directions for future CT research, including: (1) modeling for CT, (2) improving the existing test suite generation algorithm, (3) improving analysis of testing result, (4) exploring the application of CT to different levels of testing and additional types of systems, (5) conducting more empirical studies to fully understand limitations and strengths of CT, and (6) combining CT with other testing techniques. © 2011 ACM.

Zhang Y.,U.S. National Institutes of Health | Morgan M.J.,Aurora University | Chen K.,Nanjing University | Choksi S.,U.S. National Institutes of Health | Liu Z.-G.,U.S. National Institutes of Health
Blood | Year: 2012

Monocytes are programmed to undergo apoptosis in the absence of stimulation. Stimuli that promote monocyte-macrophage differentiation not only cause cellular changes, but also prevent the default apoptosis of monocytes. In the present study, we demonstrate that autophagy is induced when monocytes are triggered to differentiate and that the induction of autophagy is pivotal for the survival and differentiation of monocytes. We also show that inhibition of autophagy results in apoptosis of cells that are engaged in differentiation.We found that the differentiation signal releases Beclin1 from Bcl-2 by activating JNK and blocks Atg5 cleavage, both of which are critical for the induction of autophagy. Preventing autophagy induction hampers differentiation and cytokine production; therefore, autophagy is an important transition from monocyte apoptosis to differentiation.

Almost one-third of congenital cataracts are primarily autosomal dominant disorders, which are also called autosomal dominant congenital cataract, resulting in blindness and clouding of the lens. The purpose of this study was to identify the disease-causing mutation in a Chinese family affected by bilateral, autosomal dominant congenital cataract. The detection of candidate gene mutation and the linkage analysis of microsatellite markers were performed for the known candidate genes. Molecular mapping and cloning of candidate genes were used in all affected family members to screen for potential genetic mutations and the mutation was confirmed by single enzyme digestion. The proband was diagnosed with isolated, congenital cataract without the typical clinical manifestations of cataract, which include diabetes, porencephaly, sporadic intracerebral hemorrhage, and glomerulopathy. A novel mutation, c.2345 G > C (Gly782Ala), in exon 31 of the collagen type IV αlpha1 (COL4A1) gene, which encodes the collagen alpha-1(IV) chain, was found to be associated with autosomal dominant congenital cataract in a Chinese family. This mutation was not found in unaffected family members or in 200 unrelated controls. Sequence analysis confirmed that the Gly782 amino acid residue is highly conserved. The novel mutation (c.2345 G > C) of the COL4A1 gene is the first report of a non-syndromic, autosomal dominant congenital cataract, thereby highlighting the important role of type IV collagen in the physiological and optical properties of the lens.

Background: Life satisfaction research in China is in development, requiring new perspectives for enrichment. In China, occupational mobility is accompanied by changes in economic liberalization and the emergence of occupational stratification. On the whole, however, occupational mobility has rarely been used as an independent variable. Health status is always used as the observed or dependent variable in studies of the phenomenon and its influencing factors. A research gap still exists for enriching this field. Methods. The data used in this study were obtained from the China Health and Nutrition Survey (CHNS). The study included nine provinces in China. The survey was conducted from 1989 to 2009.Every survey involved approximately 4400 families or 19,000 individual samples and parts of community data. Results: First, we built a 5 × 5 social mobility table and calculated life satisfaction of Chinese residents of different occupations in each table. Second, gender, age, marital status, education level, annual income and hukou, health status, occupational mobility were used as independent variables. Lastly, we used logistic diagonal mobility models to analyze the relationship between life satisfaction and the variables. Model 1 was the basic model, which consisted of the standard model and controlled variables and excluded drift variables. Model 2 was the total model, which consisted of all variables of interest in this study. Model 3 was the screening model, which excluded the insignificant drift effect index in Model 2. Conclusion: From the perspective of the analysis of controlled variables, health conditions, direction, and distance of occupational mobility significantly affected life satisfaction of Chinese residents of different occupations. (1) From the perspective of health status, respondents who have not been sick or injured had better life satisfaction than those who had been sick or injured. (2) From the perspective of occupational mobility direction, the coefficients of occupational mobility in the models are less than 0, which means that upward mobility negatively affects life satisfaction. (3) From the perspective of distance, when analyzing mobility distance in Models 2 and 3, a greater distance indicates better life satisfaction. © 2014 Liang and Lu; licensee BioMed Central Ltd.

Sheng D.N.,California State University, Northridge | Gu Z.-C.,University of California at Santa Barbara | Sun K.,University of Maryland University College | Sheng L.,California State University, Northridge | Sheng L.,Nanjing University
Nature Communications | Year: 2011

It is well known that the topological phenomena with fractional excitations, the fractional quantum Hall effect, will emerge when electrons move in Landau levels. Here we show the theoretical discovery of the fractional quantum Hall effect in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically non-trivial flat-band model on a checkerboard lattice. In the presence of nearest-neighbouring repulsion, we find that at 1/3 filling, the Fermi-liquid state is unstable towards the fractional quantum Hall effect. At 1/5 filling, however, a next-nearest-neighbouring repulsion is needed for the occurrence of the 1/5 fractional quantum Hall effect when nearest-neighbouring repulsion is not too strong. We demonstrate the characteristic features of these novel states and determine the corresponding phase diagram. © 2011 Macmillan Publishers Limited. All rights reserved.

High permittivity (k) gate dielectric films are widely studied to substitute SiO 2 as gate oxides to suppress the unacceptable gate leakage current when the traditional SiO 2 gate oxide becomes ultrathin. For high-k gate oxides, several material properties are dominantly important. The first one, undoubtedly, is permittivity. It has been well studied by many groups in terms of how to obtain a higher permittivity for popular high-k oxides, like HfO 2 and La 2O 3. The second one is crystallization behavior. Although it's still under the debate whether an amorphous film is definitely better than ploy-crystallized oxide film as a gate oxide upon considering the crystal boundaries induced leakage current, the crystallization behavior should be well understood for a high-k gate oxide because it could also, to some degree, determine the permittivity of the high-k oxide. Finally, some high-k gate oxides, especially rare earth oxides (like La 2O 3), are not stable in air and very hygroscopic, forming hydroxide. This topic has been well investigated in over the years and significant progresses have been achieved. In this paper, I will intensively review the most recent progresses of the experimental and theoretical studies for preparing higher-k and more stable, in terms of hygroscopic tolerance and crystallization behavior, Hf- and La-based ternary high-k gate oxides. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Shen M.H.,Nanjing University
Zhen ci yan jiu = Acupuncture research / [Zhongguo yi xue ke xue yuan Yi xue qing bao yan jiu suo bian ji] | Year: 2012

To observe the effect of electroacupuncture (EA) of "Baihui" (GV 20) and "Dazhui" (GV 14) on the expression of gamma-glutamylcysteine synthetase (gamma-GCS) protein and gene in the cerebral cortex in rats with cerebral ischemia-reperfusion (CI/R) injury, so as to explore its molecular biological mechanism underlying anti-oxidative stress. A total of 30 male Sprague-Dawley rats were randomized into sham operation (sham, n = 10), model (n = 10), and EA (n = 10) groups. CI/R model was established by right middle cerebral artery occlusion (modified Longa's thread occlusion method) for 2 hours and reperfusion for 24 hours. EA (3 Hz, 1-3 mA) was applied to "Dazhui" (GV 14) and "Baihui" (GV 20) for 30 min. gamma-GCS protein expression of the parietotemporal region of cerebral cortex was detected by immunohistochemistry and gamma-GCS heavy subunit (gamma-GCSh) mRNA and gamma-GCS light subunit (gamma-GCSI) mRNA expression levels were assayed by real-time quantitative polymerase chain reaction (RT-PCR). Compared with the sham group, the expression levels of gamma-GCS protein in the pyramidal cell layer of the cerebral cortical parietotemporal region, and y-GCSh mRNA and gamma-GCSI mRNA, and the number of gamma-GCS immuno-reaction positive cells had no remarkable changes in the model group (P > 0.05), while in comparison with the model group, the expression levels of cerebral cortical gamma-GCS protein, and gamma-GCSh mRNA and gamma-GCSI mRNA, and the number of gamma-GCS immuno-reaction positive cells were increased considerably in the EA group (P < 0.01, P < 0.05). EA of GV 20 and GV 14 can upregulate expression levels of gamma-GCS protein, gamma-GCSh mRNA and gamma-GCSI mRNA of the cerebral cortical parietotemporal region in CI/R rats, which may contribute to its effect in protecting cerebral cortical cells from injury by clearing away excessive oxygen free radicals.

Zhang L.,University College of Applied Sciences | Zhang L.,Nanjing University | Zhang L.,Max Planck Institute for Structure and Dynamics of Material | Datta A.,University of Warwick | And 2 more authors.
Physical Review Letters | Year: 2015

Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology. © 2015 American Physical Society.

Liu Z.-H.,Nanjing University
Nature Reviews Nephrology | Year: 2013

China has a large population and a high prevalence of chronic kidney disease (CKD). The increasing incidence of obesity and type 2 diabetes mellitus, coupled with an ageing population, will exacerbate the burden of CKD unless effective control and prevention strategies are implemented. The unmet challenges of managing the growing number of patients with end-stage renal disease (ESRD) in China are reflected by the lower rate of patients receiving dialysis relative to many Western countries, owing to a lack of financial and clinical resources, and inequalities in access to health care across regions and populations. The feasibility of expanding peritoneal dialysis is being examined, and ongoing health-care reforms provide an invaluable opportunity to improve the status and quality of dialysis for patients with ESRD in China. The Chinese Society of Nephrology (CSN) advocates for efforts focused on preventing CKD coupled with early detection, treatment, and adequate follow-up to reduce mortality and the long-term burden of CKD. In addition, rapid advances in nephrology research, from basic science to clinical epidemiology, as well as broad communication and collaboration between the CSN and other international nephrology societies, will promote the development of nephrology in China. © 2013 Macmillan Publishers Limited. All rights reserved.

Li X.-H.,CAS Nanjing Institute of Geography and Limnology | Zhang Q.,CAS Nanjing Institute of Geography and Limnology | Xu C.-Y.,University of Oslo | Xu C.-Y.,Nanjing University
Journal of Hydrology | Year: 2012

Spatial rainfall is a key input to distributed hydrological models, and its precisions heavily affect the accuracy of stream flow predictions from a hydrological model. Traditional interpolation techniques which obtain the spatial rainfall distribution from rain gauge data have some limitations caused by data scarcity and bad quality, especially in developing countries or remote locations. Satellite-based precipitation products are expected to offer an alternative to ground-based rainfall estimates in the present and the foreseeable future. For this purpose, the quality and usefulness of satellite-based precipitation products need to be evaluated. The present study compares the difference of Tropical Rainfall Measuring Mission (TRMM) rainfall with rain gauges data at different time scales and evaluates the usefulness of the TRMM rainfall for hydrological processes simulation and water balance analysis at the Xinjiang catchment, located in the lower reaches of the Yangtze River in China. The results show at daily time step TRMM rainfall data are better at determining rain occurrence and mean values than at determining the rainfall extremes, and larger difference exists for the maximal daily and maximal 5-day rainfalls. At monthly time scale, good linear relationships between TRMM rainfall and rain gauges rainfall data are received with the determination coefficients (R 2) varying between 0.81 and 0.89 for the individual stations and 0.88 for areal average rainfall data, respectively. But the slope of regression line ranges between 0.74 for Yingtan and 0.94 for Yushan, indicating that the TRMM satellite is inclined to underestimate the monthly rainfall in this area. The simulation of daily hydrological processes shows that the Water Flow Model for Lake Catchment (WATLAC) model using conventional rain gauge data produces an overall good fit, but the simulation results using TRMM rainfall data are discontented. The evaluation results imply that the TRMM rainfall data are unsuited for daily stream flow simulation in this study area with desired precisions. However, good performance can be received using TRMM rainfall data for monthly stream flow simulations. The comparison of the simulated annual water balance components shows that the different rainfall data sources can change the volume value and proportion of water balance components to some extent, but it generally meets the need of practical use. © 2012 Elsevier B.V..

Luo X.,Nanjing University | Shen J.,Chinese University of Hong Kong
Habitat International | Year: 2012

In the age of globalization, new regionalism has become a new trend of regional development. This study examines the making of new regionalism in South China, using the case of Hong Kong-Shenzhen region. By tracing the process of Hong Kong and Shenzhen integration during the past three decades, the research finds three stages in Hong Kong-Shenzhen regionalization after the late 1970s, namely, the emergence of informal regional society from below, the transitional regional society and formal regional society, with reference to Hettne's concept of regionness. Hong Kong's internal economic, political and societal difficulties and external changing conditions are conducive to Hong Kong government's re-regulation toward a more positive stance on cross-boundary regionalization. Although intense economic and social interactions exist between Hong Kong and Shenzhen, a cross-boundary regional community has not emerged yet. The slow development of cross-boundary regional community is different from European case. The active participation of the governments aims to facilitate cross-boundary economic and infrastructure development and planning. This can take place well before reaching higher level of regionness: the formation of a regional community or the regional institutionalized polity. © 2011.

Ma H.,Nanjing University | Qin T.,University of Warwick | Troisi A.,University of Warwick
Journal of Chemical Theory and Computation | Year: 2014

The electronic excited states of amorphous polymeric semiconductor MEH-PPV are investigated by first principles quantum chemical calculations based on trajectories from classical molecular dynamics simulations. We inferred an average conjugation length of ∼5-7 monomers for lowest vertical excitations of amorphous MEH-PPV at room temperature and verified that the normal definition of a chromophore in a polymer based on purely geometric "conjugation breaks" is not always valid in amorphous polymers and a rigorous definition can be only on the basis of the evaluation of the polymer excited state wave function. The charge transfer character is observed to be nearly invariant for all excited states in low energy window while the exciton delocalization extent is found to increase with energy. The interchain excitonic couplings for amorphous MEH-PPV are shown to be usually smaller than 10 meV suggesting that the transport mechanism across chain can be described by incoherent hopping. All these observations about the energetic and spatial distribution of the excitons in polymer as well as their couplings provide important qualitative insights and useful quantitative information for constructing a realistic model for exciton migration dynamics in amorphous polymer materials. © 2014 American Chemical Society.

Fang J.,Nanjing University | Zhang F.,Pennsylvania State University
Monthly Weather Review | Year: 2012

Through cloud-resolving simulations, this study examines the effect of β on the evolution of tropical cyclones (TCs). It is found that the TC simulated on a β plane with variable Coriolis parameter f is weaker in intensity but larger in size and strength than the TC simulated on an f plane with constant f. Such differences result mainly from the effect of the β shear rather than from the variation of f due to the latitudinal change of the TC position, as illustrated in a three-stage conceptual model developed herein. The first stage begins with the establishment of the β shear and the emergence of asymmetries as the TC intensifies. The b shear peaks in value during the second stage that subsequently leads to the formation of an extensive stratiform region outside of the primary eyewall. The evaporative cooling associated with the stratiform precipitation acts to sharpen the low-level equivalent potential temperature gradient into a frontlike zone outside of the eyewall region, which leads to the burst of convection outside of the primary eyewall. The third stage is characterized by a weakening b shear and the corresponding TC vortex axisymmetrization and expansion. The convection on the inner edge of the stratiform region becomes more organized in the azimuthal direction and eventually causes the TC structure to evolve in a manner similar to the secondary eyewall formation and eyewall replacement usually observed in TCs. It is the active convection outside of the primary eyewall that contributes to a relatively weaker but larger TC on the β plane than that on the f plane. © 2012 American Meteorological Society.

Mou Y.,Nanjing University
International journal of nanomedicine | Year: 2011

This study investigated the influence of synthetic superparamagnetic iron oxide (SPIO) on dendritic cells and provides a possible method for labeling these cells. SPIO nanoparticles were prepared, and their morphology and magnetic properties were characterized. The particles were endocytosed by dendritic cells generated from mouse bone marrow. Labeling efficiency and cellular uptake were analyzed by Prussian blue staining and quantitative spectrophotometric assay. Meanwhile, the surface molecules, cellular apoptosis, and functional properties of the SPIO-labeled dendritic cells were explored by flow cytometry and the mixed lymphocyte reaction assay. The synthetic nanoparticles possessed a spherical shape and good superparamagnetic behavior. The mean concentration of iron in immature and mature dendritic cells was 31.8 ± 0.7 μg and 35.6 ± 1.0 μg per 1 × 10(6) cells, respectively. After 12 hours of incubation with SPIO at a concentration of 25 μg/mL, nearly all cells were shown to contain iron. Interestingly, cellular apoptosis and surface expression of CD80, CD86, major histocompatibility II, and chemokine receptor 7 in mature dendritic cells were not affected to any significant extent by SPIO labeling. T cell activation was maintained at a low ratio of dendritic cells to T cells. SPIO nanoparticles have good superparamagnetic behavior, highly biocompatible characteristics, and are suitable for use in further study of the migratory behavior and biodistribution of dendritic cells in vivo.

Mou Y.,Nanjing University
International journal of nanomedicine | Year: 2011

Successful treatment of cancer with dendritic cell tumor vaccine is highly dependent on how effectively the vaccine migrates into lymph nodes and activates T cells. In this study, a simple method was developed to trace migration of dendritic cells to lymph nodes. Superparamagnetic iron oxide (SPIO) of γ-Fe(2)O(3) nanoparticles were prepared to label dendritic cells generated from bone marrow of enhanced green fluorescent protein (EGFP) transgenic mice, to explore the fluorescence intensity of EGFP influenced by the SPIO, and to make images of labeled dendritic cells with the help of magnetic resonance imaging in vitro. The SPIO-EGFP-labeled dendritic cells were injected into the footpads of five mice. After 48 hours, magnetic resonance imaging, optical imaging, confocal imaging, and Prussian blue staining were used to confirm migration of the SPIO-EGFP-labeled dendritic cells into draining lymph nodes. The synthetic SPIO nanoparticles had a spherical shape and desirable superparamagnetism, and confocal imaging and Prussian blue staining showed perfect labeling efficiency as well. Furthermore, the dendritic cells dual-labeled by SPIO and EGFP could migrate into lymph nodes after footpad injection, and could be detected by both magnetic resonance imaging and optical imaging simultaneously, which was further confirmed by immunohistochemistry and Prussian blue staining. The percentage of dendritic cells migrated to the draining lymph nodes was about 4%. Synthetic SPIO nanoparticles are strong contrast agents with good biocompatibility, and EGFP transgenic dendritic cells can be labeled efficiently by SPIO, which are suitable for further study of the migratory behavior and biodistribution of dendritic cells in vivo.

Mao L.,Nanjing University
Archives of environmental contamination and toxicology | Year: 2010

Lignin peroxidases (LiPs) are a group of extracellular enzymes excreted by certain fungi, e.g., Phanerochaete chrysosporium. These fungi also produce veratryl alcohol (VA) as a secondary metabolite to regulate the performance of LiP. 17ss-Estradiol (E2) is a natural female hormone that is strongly endocrine disruptive when released to the natural environment. The widespread occurrence of E2 and related hormonal chemicals in soil and water environments has been identified, representing an emerging contamination of concern. We report in this study that E2 can be effectively transformed and removed through reactions mediated by LiP and such reactions are significantly enhanced in the presence of VA. We systematically investigated LiP activity and enzymatic reaction kinetics in systems having VA absent or present. The results suggest that VA enhanced the transformation and removal of E2 by the combination of two effects: (i) mitigating LiP inactivation and (ii) modifying the enzyme catalytic kinetics. These findings provide insights into an important pathway that may govern the environmental transformation of E2 and other emerging endocrine-disrupting contaminants of similar nature in the environment, and provide a basis for potential development and optimization of enzyme-based processes for remediation and removal of these contaminants.

Chen B.,Nanjing University | Yin Y.,Nanjing University of Information Science and Technology
Journal of Geophysical Research: Atmospheres | Year: 2011

Overshooting deep convection plays an important role in regulating the water vapor content of the tropical tropopause layer and is also an important mechanism for transporting water vapor into the lower stratosphere (LS). The aim of this study is to examine the effect of aerosols as cloud condensation nuclei (CCN) on the water vapor content of the LS via single isolated overshooting thunderstorms. The development of a severe Hector thunderstorm in northern Australia observed during the Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere/Aerosol and Chemical Transport in Tropical Convection (SCOUT-O3/ACTIVE) campaign is simulated using a three-dimensional nonhydrostatic convective cloud model with a double-moment bulk microphysics scheme. The results show that the ice hydrometeors account for over 50% of the total condensate mass, indicating that ice processes play an important role in regulating the structure of thunderstorms in the tropics. A large number of ice particles occurring in the LS are not formed in situ but are transported upward by convective overshooting with subsequent mixing. Sensitivity tests show that the increase in cloud droplet numbers induced by increasing CCN concentrations would increase the number concentrations of the ice crystals transported to the LS, which had the effect of reducing the sizes and fall speeds of the ice crystal, thereby causing a moistening of the LS by sublimation of the injected ice particles. This result suggests that aerosols in the boundary layer can affect stratospheric water vapor via overshooting deep convection. Copyright © 2011 by the American Geophysical Union.

Sun Z.-W.,Nanjing University
Electronic Journal of Combinatorics | Year: 2013

In this paper we study products and sums divisible by central binomial coefficients. We show that Also, for any nonnegative integers κ and n we have and where Cm denotes the Catalan number. On the basis of these results, we obtain certain sums divisible by central binomial coefficients.

Jin F.,Geotechnical Research Group | Gu K.,Nanjing University | Al-Tabbaa A.,Geotechnical Research Group
Cement and Concrete Composites | Year: 2015

Ground granulated blastfurnace slag (GGBS) is widely used as a partial replacement for Portland cement or as the major component in the alkali-activated cement to give a clinker-free binder. In this study, reactive MgO is investigated as a potentially more practical and greener alternative as a GGBS activator. This paper focuses on of the hydration of GGBS, activated by two commercial reactive MgOs, with contents ranging from 2.5% to 20% up to 90 days. The hydration kinetics and products of MgO-GGBS blends were investigated by selective dissolution, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy techniques. It was found that reactive MgO was more effective than hydrated lime in activating the GGBS based on unconfined compressive strength and the efficiency increased with the reactivity and the content of the MgO. It is hence proposed that reactive MgO has the potential to serve as an effective and economical activator for GGBS. © 2014 Elsevier Ltd. All rights reserved.

Gu Z.,Jiangsu Engineering Research Center for Micro Biology and Biotechnology | Gu Z.,Nanjing University | Wang J.,Jiangsu Engineering Research Center for Micro Biology and Biotechnology
Bioinformatics | Year: 2013

Summary: CePa is an R package aiming to find significant pathways through network topology information. The package has several advantages compared with current pathway enrichment tools. First, pathway node instead of single gene is taken as the basic unit when analysing networks to meet the fact that genes must be constructed into complexes to hold normal functions. Second, multiple network centralities are applied simultaneously to measure importance of nodes from different aspects to make a full view on the biological system. CePa extends standard pathway enrichment methods, which include both over-representation analysis procedure and gene-set analysis procedure. CePa has been evaluated with high performance on real-world data, and it can provide more information directly related to current biological problems. © 2013 The Author Published by Oxford University Press. All rights reserved.

Gao C.,Nanjing University | Zhang T.,CAS Nanjing Institute of Soil Science
Ambio | Year: 2010

Eutrophication is now a ubiquitous water quality impairment in China. The first step toward restoration of eutrophicated water bodies is a marked reduction of nutrient loadings in their drainage basins. However, the combination of a number of physical and socio-economic factors is now producing compounded increases in nutrient loads while the nutrient assimilation capacities of natural systems are decreasing. Meanwhile, most of the lakes in densely populated part of China are shallow and very susceptible to anthropogenic alteration. Therefore, in spite of ascending efforts in eutrophication control upward trends of algal blooms in both fresh and coastal waters have been observed for the past two decades. Huge knowledge gap exists in our understanding of the sources and pathways of nutrient losses to aquatic ecosystems. Successful water quality restoration of China's eutrophic waters relies not only on more resource input but also more emphasis on basic, integrated, and management-oriented research. © 2010 Royal Swedish Academy of Sciences.

Luo W.,National Renewable Energy Laboratory | Li Z.,National Renewable Energy Laboratory | Li Z.,Nanjing University | Yu T.,National Renewable Energy Laboratory | Zou Z.,National Renewable Energy Laboratory
Journal of Physical Chemistry C | Year: 2012

The surface pretreatment by electrochemical cyclic voltammetry (CV) in the dark was found to remarkably enhance the photocurrent of Mo-doped BiVO 4 from the front side illumination. The variation of the samples before and after the surface pretreatment was investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, and Mott-Schottky methods. The results showed that the photocurrent enhancement came from both the removal of the surface recombination center, including Mo 6+ ions, and reoxidation of the reduced species. The part of the reduced ions can be reoxidized in air. However, the photocurrent enhancement from the Mo 6+ dissolution can be kept at high potential under illumination. A possible mechanism was also proposed to explain the reason for the photocurrent enhancement. © 2012 American Chemical Society.

Zheng X.M.,Nanjing University
Environmental science and pollution research international | Year: 2011

Perfluorinated compounds (PFCs) have been widely used in industrial and consumer products and frequently detected in many environmental media. Potential reproductive effects of perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) have been reported in mice, rats and water birds. PFOS and PFOA were also confirmed developing toxicants towards zebrafish embryos; however, the reported effect concentrations were contradictory. Polyfluorinated alkylated phosphate ester surfactants (including FC807) are precursor of PFOS and PFOA; however, there is no published information about the effects of FC807 and PFNA on zebrafish embryos. Therefore, this study was conducted to determine the effects of these four PFCs on zebrafish embryos. Normal fertilized zebrafish embryos were selected to be exposed to several concentrations of PFOA, PFNA, PFOS or FC807 in 24-well cell culture plates. A digital camera was used to image morphological anomalies of embryos with a stereomicroscope. Embryos were observed through matching up to 96-h post-fertilization (hpf) and rates of survival and abnormalities recorded. PFCs caused lethality in a concentration-dependent manner with potential toxicity in the order of PFOS > FC807 > PFNA > PFOA based on 72-h LC(50). Forty-eight-hour post-fertilization pericardial edema and 72- or 96-hpf spine crooked malformation were all observed. PFOA, PFNA, PFOS and FC807 all caused structural abnormalities using early stages of development of zebrafish. The PFCs all retarded the development of zebrafish embryos. The toxicity of the PFCs was related to the length of the PFC chain and functional groups.

Li B.,Tsinghua University | Cao H.,Tsinghua University | Yin G.,Nanjing University | Lu Y.,Tsinghua University | Yin J.,Tsinghua University
Journal of Materials Chemistry | Year: 2011

Cu2O@reduced graphene oxide composite displays a good ability to remove dyes from water and high stability in supercapacitors, highlighting potential applications in environmental and energy storage issues. © 2011 The Royal Society of Chemistry.

Zhao Q.,Nanjing University
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica | Year: 2012

To explore the potential mechanisms of huangkui capsule (HKC), an extract from Abelmoschus manihot (AM), for ameliorating renal inflammatory injury by regulating p38 mitogen-activated protein kinase (MAPK) signaling pathway in rats with adriamycin-induced nephropathy (ADRN). Nineteen Sprague-Dawley (SD) rats were randomly divided into three groups, the sham-operation group, the untreated model group,and the HKC-treated group. Rats in the untreated model group and the HKC-treated group were made into ADRN model by right nephrectomy and twice intravenous injections of adriamycin( ADR, 0.4 mL and 0.2 mL respectively within 4 weeks). After the model successfully established, rats in the HKC-treated group were orally given HKC (2 mg x kg(-1) per day), while rats in the untreated model group and the sham-operation group were intervened with distilled water respectively. The intervention for all rats was 4 weeks. Rats' body weight were weighted and 24 h urinary protein excretion (Upro) was detected at the end of the 1st, 2nd, 3rd, and 4th week after the intervention of HKC or distilled water. All rats were sacrificed at the end of the 8th week after nephrectomy, and then, to withdraw blood and kidney to examine the blood biochemical parameters, the glomerular morphological changes, alpha-smooth muscle actin (alpha-SMA) and collagen type I expressions,and the glomerular macrophages infiltration. Besides, the protein expression of transforming growth factor (TGF)-beta1, p38MAPK, as well as phosphorylated p38MAPK (p-p38MAPK) in renal tissues were detected by Western blotting. As compared with rats in the untreated model group, in the HKC-treated group,the HKC treatment significantly improved Upro, serum albumin, mesangial cell proliferation, extracellular matrix (ECM) and collagen deposition,and decreased the expression of alpha-SMA and collagen type I and the infiltration of ED1+ and ED3+ cells in glomeruli. In addition, it significantly down-regulated the protein expression of TGF-beta1 and p-p38MAPK in renal tissues. HKC had the effects on ameliorating renal inflammatory injury in vivo. It could reduce the expression of TGF-beta1 and improve the infiltration and activation of inflammatory cells in glomeruli by way of intervening p38MAPK signaling pathway in kidney through down-regulating the protein expression of p-p38MAPK, as the key signal molecule.

Zhou Y.,Nanjing University | Loh K.P.,National University of Singapore
Advanced Materials | Year: 2010

Craphene-based nanostructures are considered as promising alternatives to silicon-based mesostructures in future electronic nanodevices. The lithographical patterning of graphene, which are essential steps in any form of microelectronic processing, present interesting challenges because of the atomic layer thickness of graphene. Mesoscopic devices based on graphene require high spatial resolution patterning that will induce as little damage as possible. This research news highlights and evaluates recent developments in the nanostructuring and patterning of graphene. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fa W.,Nanjing University | Zeng X.C.,University of Nebraska - Lincoln
Chemical Communications | Year: 2014

Successful synthesis of the phenylisopropyl hexagermane (Chem. Commun. 2013, 49, 8380) offers an exciting opportunity to synthesize a new class of low-dimensional germanium compounds with novel optical and electronic properties. Using the phenylisopropyl hexagermane as a model template, we have performed an ab initio study of electronic properties of polygermanes. Our density functional theory calculations show that the polygermane is a quasi-one-dimensional semiconductor with a direct bandgap, and its valence and conduction bands are mainly contributed by the skeletal Ge atoms. We have also explored effects of tensile and compressive strains and various side-chain substituents on the bandgap. The bandgap of polygermanes can be reduced upon attaching larger-sized substituents to the side chains. More importantly, applying a tensile/compressive strain can modify the bandgap of polygermanes over a wide range. For poly(diphenlygermane), the tensile strain can result in significant bandgap reduction due to the increasingly delocalized charge density in the conduction band. Moreover, a strong compressive strain can induce a direct-to-indirect semiconductor transition owing to the change made in the band-edge states. A similar strain effect is seen in polystannanes as well. This journal is © the Partner Organisations 2014.

Jian Z.,Japan National Institute of Advanced Industrial Science and Technology | Liu P.,Tohoku University | Li F.,Japan National Institute of Advanced Industrial Science and Technology | He P.,Nanjing University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014

A RuO2 shell was uniformly coated on the surface of core CNTs by a simple sol-gel method, and the resulting composite was used as a catalyst in a rechargeable Li-O2 battery. This core-shell structure can effectively prevent direct contact between the CNT and the discharge product Li2O2, thus avoiding or reducing the formation of Li 2CO3, which can induce large polarization and lead to charge failure. The battery showed a high round-trip efficiency (ca. 79 %), with discharge and charge overpotentials of 0.21 and 0.51V, respectively, at a current of 100mA gtotal-1. The battery also exhibited excellent rate and cycling performance. Get your battery going: Core-shell-structured CNT@RuO2, a good catalyst for oxygen-reduction and oxygen-evolution reactions, was used to construct a Li-O2 battery with a low overpotential (0.72V) and thus a high round-trip efficiency (ca. 79 %). By preventing the direct contact of Li2O2 with the carbon nanotube (CNT), the uniform RuO2 coating hinders the formation of Li2CO3 to improve round-trip efficiency and cycling performance (see picture). © 2014 WILEY-VCH Verlag GmbH.

Xiao Y.,Nanyang Technological University | Wu J.,Nanjing University | Yuan J.,Nanyang Technological University
IEEE Transactions on Image Processing | Year: 2014

mCENTRIST, a new multichannel feature generation mechanism for recognizing scene categories, is proposed in this paper. mCENTRIST explicitly captures the image properties that are encoded jointly by two image channels, which is different from popular multichannel descriptors. In order to avoid the curse of dimensionality, tradeoffs at both feature and channel levels have been executed to make mCENTRIST computationally practical. As a result, mCENTRIST is both efficient and easy to implement. In addition, a hyperopponent color space is proposed by embedding Sobel information into the opponent color space for further performance improvements. Experiments show that mCENTRIST outperforms established multichannel descriptors on four RGB and RGB-near infrared data sets, including aerial orthoimagery, indoor, and outdoor scene category recognition tasks. Experiments also verify that the hyper opponent color space enhances descriptors' performance effectively. © 2013 IEEE.

Zhang S.J.,Nanjing University
Zhongguo zhen jiu = Chinese acupuncture & moxibustion | Year: 2013

The origin and development of the Ashi point theory are arranged, it is believed that the essence of Ashi point is a point locating method and it is suitable for the location of each acupoint. Originated from Neijing (Internal Classic), this method is the primary point locating method in ancient times, corresponding to the forms of acupoints in Neijing (Internal Classic), the points are located though palpation. This point locating method can be widely used to locate the points clinically, what's more, the Ashi method is not limited to use for local tenderness. Ashi point got its conception from Qianjin Yao fang (Prescriptions Worth a Thousand Gold), under the background of acupoint channel tropism, it gradually evolved to a certain kind of point that parallel to the regular point and extra point. This process changed the clinical point locating method: regular point and extra point are located according to proportional bone measurement, while Ashi point is located by palpation. However, it betrays the classic and clinical practice gradually.

Huang B.,Nanjing Audit University | Li H.-X.,Nanjing University | Wei D.-K.,Hunan University of Science and Technology
Knowledge-Based Systems | Year: 2012

Intuitionistic fuzzy information systems are generalized types of conventional fuzzy-valued information systems. By introducing a dominance relation to intuitionistic fuzzy information systems, we propose a notion of dominance intuitionistic fuzzy information systems (DIFIS) and establish a dominance-based rough set model, which is mainly based on the substitution of the indiscernibility relation in classic rough set theory by a dominance relation that is defined on the score and accuracy function of intuitionistic fuzzy value in DIFIS. Furthermore, to simplify the knowledge representation and extract useful and simpler dominance intuitionistic fuzzy rules, we provide two attribute reduction approaches to eliminate the redundant information. Finally, we apply these approaches to computer auditing risk assessment, and by using an application as a case study we acquire some valuable assessment rules. These resulting rules can provide an available method to acquire knowledge from DIFISs. © 2011 Elsevier B.V. All rights reserved.