Showing papers by "Shanghai University published in 2011"
TL;DR: The development of porphysomes; nanovesicles formed from self-assembled porphyrin bilayers that generated large, tunable extinction coefficients, structure-dependent fluorescence self-quenching and unique photothermal and photoacoustic properties demonstrate the multimodal potential of organic nanoparticles for biophotonic imaging and therapy.
Abstract: Optically active nanomaterials promise to advance a range of biophotonic techniques through nanoscale optical effects and integration of multiple imaging and therapeutic modalities. Here, we report the development of porphysomes; nanovesicles formed from self-assembled porphyrin bilayers that generated large, tunable extinction coefficients, structure-dependent fluorescence self-quenching and unique photothermal and photoacoustic properties. Porphysomes enabled the sensitive visualization of lymphatic systems using photoacoustic tomography. Near-infrared fluorescence generation could be restored on dissociation, creating opportunities for low-background fluorescence imaging. As a result of their organic nature, porphysomes were enzymatically biodegradable and induced minimal acute toxicity in mice with intravenous doses of 1,000 mg kg^(−1). In a similar manner to liposomes, the large aqueous core of porphysomes could be passively or actively loaded. Following systemic administration, porphysomes accumulated in tumours of xenograft-bearing mice and laser irradiation induced photothermal tumour ablation. The optical properties and biocompatibility of porphysomes demonstrate the multimodal potential of organic nanoparticles for biophotonic imaging and therapy.
1,147 citations
TL;DR: In this article, a comprehensive study on the toxicity of graphene oxide (GO) by examining the influences of GO on the morphology, viability, mortality and membrane integrity of A549 cells was performed.
1,075 citations
TL;DR: This work proposes a novel reversible data hiding scheme for encrypted image, where the additional data can be embedded into the image by modifying a small proportion of encrypted data.
Abstract: This work proposes a novel reversible data hiding scheme for encrypted image. After encrypting the entire data of an uncompressed image by a stream cipher, the additional data can be embedded into the image by modifying a small proportion of encrypted data. With an encrypted image containing additional data, one may firstly decrypt it using the encryption key, and the decrypted version is similar to the original image. According to the data-hiding key, with the aid of spatial correlation in natural image, the embedded data can be successfully extracted and the original image can be perfectly recovered.
768 citations
01 Jul 2011
TL;DR: Graphene oxide is a highly effective absorbent of methylene blue (MB) and can be used to remove MB from aqueous solution and the results indicate that GO can be applied in treating industrial effluent and contaminated natural water.
Abstract: Graphene oxide (GO) is a highly effective absorbent of methylene blue (MB) and can be used to remove MB from aqueous solution. A huge absorption capacity of 714 mg/g is observed. At initial MB concentrations lower than 250 mg/L, the removal efficiency is higher than 99% and the solution can be decolorized to nearly colorless. The removal process is fast and more efficient at lower temperatures and higher pH values. The increase of ionic strength and the presence of dissolved organic matter would further enhance the removal process when MB concentration is high. The results indicate that GO can be applied in treating industrial effluent and contaminated natural water. The implications to graphene-based environmental technologies are discussed.
593 citations
TL;DR: It is confirmed that POA bound to RpsA (but not a clinically identified ΔAla mutant) and subsequently inhibited trans-translation rather than canonical translation, and its inhibition may explain the ability of PZA to eradicate persisting organisms.
Abstract: Pyrazinamide (PZA) is a first-line tuberculosis drug that plays a unique role in shortening the duration of tuberculosis chemotherapy. PZA is hydrolyzed intracellularly to pyrazinoic acid (POA) by pyrazinamidase (PZase, encoded by pncA), an enzyme frequently lost in PZA-resistant strains, but the target of POA in Mycobacterium tuberculosis has remained elusive. Here, we identify a previously unknown target of POA as the ribosomal protein S1 (RpsA), a vital protein involved in protein translation and the ribosome-sparing process of trans-translation. Three PZA-resistant clinical isolates without pncA mutation harbored RpsA mutations. RpsA overexpression conferred increased PZA resistance, and we confirmed that POA bound to RpsA (but not a clinically identified ΔAla mutant) and subsequently inhibited trans-translation rather than canonical translation. Trans-translation is essential for freeing scarce ribosomes in nonreplicating organisms, and its inhibition may explain the ability of PZA to eradicate persisting organisms.
468 citations
TL;DR: Chromophoric iridium(III) complex-coated NaYF nanocrystals are demonstrated as a ratiometric upconversion luminescence (UCL) probe for highly selective detection of cyanide anion and bioimaging of CN(-) in living cells through inhibition of the energy transfer from the UCL of the nanocry crystals to the absorbance of the chromophoric complex.
Abstract: Chromophoric iridium(III) complex-coated NaYF4: 20%Yb, 1.6%Er, 0.4%Tm nanocrystals are demonstrated as a ratiometric upconversion luminescence (UCL) probe for highly selective detection of cyanide anion and bioimaging of CN– in living cells through inhibition of the energy transfer from the UCL of the nanocrystals to the absorbance of the chromophoric complex. The UCL probe provides a very low detection limit of 0.18 μM CN– in the aqueous solution.
366 citations
TL;DR: In this paper, the authors summarized the development of the use of layered double hydroxides (LDHs) and their derivatives as heterogeneous and recyclable catalysts/catalyst supports for various reactions in the period of 2005 to early 2010.
344 citations
TL;DR: The sheet-on-sheet nanocomposite showed highly reversible large capacities at a common current of 0.1 C and good rate capabilities, and it is believed that the mechanical stability and electrical conductivity of NiO nanosheets are increased by graphene nanOSheets (GNS).
Abstract: This paper reports a hydrothermal preparation of NiO–graphene sheet-on-sheet and nanoparticle-on-sheet nanostructures. The sheet-on-sheet nanocomposite showed highly reversible large capacities at a common current of 0.1 C and good rate capabilities. A large initial charge capacity of 1056 mAh/g was observed for the sheet-on-sheet composite at 0.1 C, which decreased by only 2.4% to 1031 mAh/g after 40 cycles of discharge and charge. This cycling performance is better than that of NiO nanosheets, graphene nanosheets, NiO-graphene nanoparticle-on-sheet, and previous carbon/carbon nanotube supported NiO composites. It is believed that the mechanical stability and electrical conductivity of NiO nanosheets are increased by graphene nanosheets (GNS), the aggregation or restacking of which to graphite platelets are, on the other hand, effectively prevented by NiO nanosheets.
340 citations
TL;DR: This paper presents a collection of Raman spectra of 18 kinds of amino acids and their aqueous solutions that can serve as references for the interpretation of RamaSpectra of proteins and biological materials.
338 citations
TL;DR: In this paper, the authors show that the two approaches are strongly related and potentially equivalent, so that the inverse-engineering operations in one of them can be interpreted and understood in terms of the concepts and operations of the other one.
Abstract: Different methods have been recently put forward and implemented experimentally to inverse engineer the time-dependent Hamiltonian of a quantum system and accelerate slow adiabatic processes via nonadiabatic shortcuts. In the ``transitionless quantum driving'' proposed by Berry, shortcut Hamiltonians are designed so that the system follows exactly, in an arbitrarily short time, the approximate adiabatic path defined by a reference Hamiltonian. A different approach is based on first designing a Lewis-Riesenfeld invariant to carry the eigenstates of a Hamiltonian from specified initial to final configurations, again in an arbitrary time, and then constructing from the invariant the transient Hamiltonian that connects these boundary configurations. We show that the two approaches, apparently quite different in form and so far in results, are, in fact, strongly related and potentially equivalent, so that the inverse-engineering operations in one of them can be reinterpreted and understood in terms of the concepts and operations of the other one. We study, as explicit examples, expansions of time-dependent harmonic traps and the state preparation of two-level systems.
315 citations
TL;DR: Based on the strong interaction between single-stranded DNA (ssDNA) and graphene material, a simple but smart platform was designed in this article to fabricate electrochemical biosensors by using graphene quantum dots modified pyrolytic graphite electrode coupled with specific sequence ssDNA molecules as probes.
TL;DR: A brief overview on the recent stability results of fractional differential equations and the analytical methods used are provided in this paper, where some conclusions for stability are similar to that of classical integer-order differential equations.
Abstract: Recently, fractional calculus has attracted much attention since it plays an important role in many fields of science and engineering. Especially, the study on stability of fractional differential equations appears to be very important. In this paper, a brief overview on the recent stability results of fractional differential equations and the analytical methods used are provided. These equations include linear fractional differential equations, nonlinear fractional differential equations, fractional differential equations with time-delay. Some conclusions for stability are similar to that of classical integer-order differential equations. However, not all of the stability conditions are parallel to the corresponding classical integer-order differential equations because of non-locality and weak singularities of fractional calculus. Some results and remarks are also included.
TL;DR: This work shows that metabolomic profiling approach is a promising screening tool for the diagnosis and stratification of HCC patients with alpha fetoprotein values lower than 20 ng/ml with an accuracy of 100% using a panel of metabolite markers.
TL;DR: The time-space fractional order (fractional for simplicity) nonlinear subdiffusion and superdiffusion equations, which can relate the matter flux vector to concentration gradient in the general sense, describing, for example, the phenomena of anomalous diffusion, fractional Brownian motion, and so on are studied.
Abstract: In this paper, we study the time-space fractional order (fractional for simplicity) nonlinear subdiffusion and superdiffusion equations, which can relate the matter flux vector to concentration gradient in the general sense, describing, for example, the phenomena of anomalous diffusion, fractional Brownian motion, and so on. The semi-discrete and fully discrete numerical approximations are both analyzed, where the Galerkin finite element method for the space Riemann-Liouville fractional derivative with order 1+@b@?[1,2] and the finite difference scheme for the time Caputo derivative with order @a@?(0,1) (for subdiffusion) and (1,2) (for superdiffusion) are analyzed, respectively. Results on the existence and uniqueness of the weak solutions, the numerical stability, and the error estimates are presented. Numerical examples are included to confirm the theoretical analysis. During our simulations, an interesting diffusion phenomenon of particles is observed, that is, on average, the diffusion velocity for 0<@a<1 is slower than that for @a=1, but the diffusion velocity for 1<@a<2 is faster than that for @a=1. For the spatial diffusion, we have a similar observation.
TL;DR: In this article, a modified Hummer method is used to fabricate unique two-dimensional graphene/NiO composite material, where the NiO nanoparticles are uniformly dispersed on the surface of graphene, which greatly increases the surface area of the composite (134.5 m2 g−1).
Abstract: In this paper, graphene oxide (GO) synthesized from the modified Hummer method is used directly to fabricate unique two-dimension graphene/NiO composite material. Nickel ions are adsorbed on both sides of GO based on self-assembly by the electrostatic interactions of two species, forming the monolayer graphene/NiO sheet. The as-prepared composite is characterized using X-ray diffraction (XRD), Raman, SEM, TEM, Energy Dispersive Spectrometer (EDS) analysis and nitrogen adsorption/desorption. The results demonstrate that the NiO nanoparticles (5–7 nm) is uniformly dispersed on the surface of graphene, which greatly increases the surface area of the composite (134.5 m2 g−1). This two-dimensional structure enhances supercapacitive performance with a high specific capacitance of 525 F g−1 at a current density of 200 mA g−1. A capacity retention of 95.4% can be maintained after 1000 cycles, suggesting its promising potential in supercapacitors.
TL;DR: In this paper, generalized power control strategies based on symmetric-sequence components are proposed to manipulate the delivered instantaneous power under unbalanced voltage dips, and two strategies for simultaneous active and reactive power control are proposed that preserve flexible controllability.
Abstract: During voltage dips continuous power delivery from distributed generation systems to the grid is desirable for the purpose of grid support. In order to facilitate the control of inverter-based distributed power generation adapted to the expected change of grid requirements, generalized power control strategies based on symmetric-sequence components are proposed in this paper, aiming to manipulate the delivered instantaneous power under unbalanced voltage dips. It is shown that active and reactive power can be independently controlled with two individually adaptable parameters. By changing these parameters, the relative amplitudes of oscillating power can be smoothly regulated, as well as the peak values of three-phase grid currents. As a result, the power control of grid-interactive inverters becomes quite flexible and adaptable to various grid requirements or design constraints. Furthermore, two strategies for simultaneous active and reactive power control are proposed that preserve flexible controllability; an application example is given to illustrate the simplicity and adaptability of the proposed strategies for online optimization control. Finally, experimental results are provided that verify the proposed power control.
TL;DR: In this article, the authors developed an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD) region for the year 2007.
Abstract: . The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD) region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP). The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.
TL;DR: The nanoprobe N719-UCNPs has been shown to be capable of monitoring changes in the distribution of Hg(2+) in living cells by upconversion luminescence bioimaging.
Abstract: A chromophoric ruthenium complex-assembled nanophosphor (N719-UCNPs) was achieved as a highly selective water-soluble probe for upconversion luminescence sensing and bioimaging of intracellular mercury ions. The prepared nanophosphors were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDXA), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Further application of N719-UCNPs in sensing Hg2+ was confirmed by optical titration experiment and upconversion luminescence live cell imaging. Using the ratiometric upconversion luminescence as a detection signal, the detection limit of Hg2+ for this nanoprobe in water was down to 1.95 ppb, lower than the maximum level (2 ppb) of Hg2+ in drinking water set by the United States EPA. Importantly, the nanoprobe N719-UCNPs has been shown to be capable of monitoring changes in the distribution of Hg2+ in living cells by upconversion luminescence bioimaging.
TL;DR: In this article, the important properties of the Riemann-Liouville (RL) derivative, one of the most commonly used fractional derivatives, are discussed, and the partial fractional derivative is also introduced.
Abstract: Recently, many models are formulated in terms of fractional derivatives, such as in control processing, viscoelasticity, signal processing, and anomalous diffusion. In the present paper, we further study the important properties of the Riemann-Liouville (RL) derivative, one of mostly used fractional
derivatives. Some important properties of the Caputo derivative which have not been discussed elsewhere are simultaneously mentioned. The partial fractional derivatives are also introduced. These discussions are beneficial in understanding fractional calculus and modeling fractional equations in science and engineering.
TL;DR: A hierarchical Sn@CNT nanostructure rooted in graphene exhibits larger than theoretical reversible capacities of 1160-982 mAh/g in 100 cycles at 100 mA/g and excellent rate capability and excellent electrochemical performances compared to graphene/Sn-based anodes.
Abstract: Development of materials with carefully crafted nanostructures has been an important strategy for the next-generation lithium-ion batteries to achieve higher capacity, longer cycle life, and better rate capability. Graphene-based and Sn-based anode materials are promising anodes with higher capacities than graphite; however, most of them exhibit fast capacity fading at prolonged cycling and poor rate capability. This paper reports a hierarchical Sn@CNT nanostructure rooted in graphene, which exhibits larger than theoretical reversible capacities of 1160–982 mAh/g in 100 cycles at 100 mA/g and excellent rate capability (828 mAh/g at 1000 mA/g and 594 mAh/g at 5000 mA/g). The excellent electrochemical performances compared to graphene/Sn-based anodes have been attributed to the efficient prevention of graphene agglomeration by Sn@CNT decoration and the increased electrochemical activities of Sn by CNT shell protection and GNS support.
TL;DR: A discovery algorithm of associated resources is first proposed to build original ALN for organizing loose Web resources and an application using C-ALN to organize Web services is presented, which shows that C- ALN is an effective and efficient tool for building semantic link on the resources of Web services.
Abstract: Association Link Network (ALN) aims to establish associated relations among various resources. By extending the hyperlink network World Wide Web to an association-rich network, ALN is able to effectively support Web intelligence activities such as Web browsing, Web knowledge discovery, and publishing, etc. Since existing methods for building semantic link on Web resources cannot effectively and automatically organize loose Web resources, effective Web intelligence activities are still challenging. In this paper, a discovery algorithm of associated resources is first proposed to build original ALN for organizing loose Web resources. Second, three schemas for constructing kernel ALN and connection-rich ALN (C-ALN) are developed gradually to optimize the organizing of Web resources. After that, properties of different types of ALN are discussed, which show that C-ALN has good performances to support Web intelligence activities. Moreover, an evaluation method is presented to verify the correctness of C-ALN for semantic link on documents. Finally, an application using C-ALN to organize Web services is presented, which shows that C-ALN is an effective and efficient tool for building semantic link on the resources of Web services.
TL;DR: The experimental results indicate potential applications of LPP-based FE and Gaussian mixture model (GMM)-based negative log likelihood probability (NLLP) as effective tools for bearing performance degradation assessment.
TL;DR: In this paper, the authors use the dynamical invariants associated with the Hamiltonian of an atom in a one dimensional moving trap to inverse engineer the trap motion and perform fast atomic transport without final vibrational heating.
Abstract: We use the dynamical invariants associated with the Hamiltonian of an atom in a one dimensional moving trap to inverse engineer the trap motion and perform fast atomic transport without final vibrational heating. The atom is driven nonadiabatically through a shortcut to the result of adiabatic, slow trap motion. For harmonic potentials this only requires designing appropriate trap trajectories, whereas perfect transport in anharmonic traps may be achieved by applying an extra field to compensate the forces in the rest frame of the trap. The results can be extended to atom stopping or launching. The limitations due to geometrical constraints, energies, and accelerations involved are analyzed along with the relation to previous approaches based on classical trajectories or ``fast-forward'' and ``bang-bang'' methods, which can be integrated in the invariant-based framework.
TL;DR: A reliability-guided displacement scanning strategy is employed to avoid time-consuming integer–pixel displacement searching for each calculation point, and a pre-computed global interpolation coefficient look-up table is utilized to entirely eliminate repetitive interpolation calculation at sub-pixel locations.
TL;DR: Two studies provide novel insights into the genetic control and molecular mechanism of BMP signaling during cartilage development by finding that BMP2 enhances Runx2 protein levels through inhibition of CDK4 and subsequent prevention of Runx 2 ubiquitylation and proteasomal degradation.
Abstract: The BMP signaling pathway has a crucial role in chondrocyte proliferation and maturation during endochondral bone development. To investigate the specific function of the Bmp2 and Bmp4 genes in growth plate chondrocytes during cartilage development, we generated chondrocyte-specific Bmp2 and Bmp4 conditional knockout (cKO) mice and Bmp2,Bmp4 double knockout (dKO) mice. We found that deletion of Bmp2 and Bmp4 genes or the Bmp2 gene alone results in a severe chondrodysplasia phenotype, whereas deletion of the Bmp4 gene alone produces a minor cartilage phenotype. Both dKO and Bmp2 cKO mice exhibit severe disorganization of chondrocytes within the growth plate region and display profound defects in chondrocyte proliferation, differentiation and apoptosis. To understand the mechanism by which BMP2 regulates these processes, we explored the specific relationship between BMP2 and Runx2, a key regulator of chondrocyte differentiation. We found that BMP2 induces Runx2 expression at both the transcriptional and post-transcriptional levels. BMP2 enhances Runx2 protein levels through inhibition of CDK4 and subsequent prevention of Runx2 ubiquitylation and proteasomal degradation. Our studies provide novel insights into the genetic control and molecular mechanism of BMP signaling during cartilage development.
TL;DR: In this article, a single particle laser desorption/ionization time of flight mass spectrometer capable of determining the size and chemical compositions of individual aerosol particles in real-time was presented.
TL;DR: This paper uses higher order piecewise interpolation polynomial to approximate the fractional integral and fractional derivatives, and uses the Simpson method to design a higher order algorithm for the fractionsal differential equations.
TL;DR: Anatase TiO(2) nanosheets-based hierarchical spheres with over 90% {001} facets synthesized via a diethylene glycol-solvothermal route were used as photoanodes of dye-sensitized solar cells, which generated an energy conversion efficiency of 7.51%.
TL;DR: An effective memetic differential evolution (DE) algorithm that utilizes a chaotic local search (CLS) with a 'shrinking' strategy that is significantly better than, or at least comparable to, the other optimizers in terms of convergence performance and solution accuracy.
TL;DR: Reversible addition−fragmentation chain transfer (RAFT) aqueous dispersion polymerization was used to synthesize a novel type of core−shell nanogel containing linear poly( methylene glycol) (PEG) and/or nonlinear polymers with oligo(ethylene gly col) side chains with enhanced stability in comparison with molecularly dissolved polymers.
Abstract: Reversible addition−fragmentation chain transfer (RAFT) aqueous dispersion polymerization was used to synthesize a novel type of core−shell nanogel containing linear poly(ethylene glycol) (PEG) and/or nonlinear polymers with oligo(ethylene glycol) side chains. These nanogels with low polydispersities were synthesized efficiently with tunable sizes and thermosensitivities. The nanogels containing nonlinear polymers with oligo(ethylene glycol) side chains as the shell had enhanced stability during freeze−thawing process and in biologically relevant solutions including 1.5 M NaCl, 1% bovine serum albumin (BSA) and 100% fetal bovine serum (FBS) solutions. Aminolysis and hydrolysis of the chain transfer agents (CTAs) in the nanogels were studied and the nanogels exhibited enhanced stability in comparison with molecularly dissolved polymers. The chemical stability of the CTAs in the nanogels was well-correlated with the in vitro cell viability studies of the nanogels using lung cancer cells.