Showing papers by "Xiamen University published in 2006"
TL;DR: It is reported that genetically and antigenically distinct sublineages of H5N1 virus have become established in poultry in different geographical regions of Southeast Asia, indicating the long-term endemicity of the virus, and the isolation of H3N2 virus from apparently healthy migratory birds in southern China.
Abstract: Preparedness for a possible influenza pandemic caused by highly pathogenic avian influenza A subtype H5N1 has become a global priority. The spread of the virus to Europe and continued human infection in Southeast Asia have heightened pandemic concern. It remains unknown from where the pandemic strain may emerge; current attention is directed at Vietnam, Thailand, and, more recently, Indonesia and China. Here, we report that genetically and antigenically distinct sublineages of H5N1 virus have become established in poultry in different geographical regions of Southeast Asia, indicating the long-term endemicity of the virus, and the isolation of H5N1 virus from apparently healthy migratory birds in southern China. Our data show that H5N1 influenza virus, has continued to spread from its established source in southern China to other regions through transport of poultry and bird migration. The identification of regionally distinct sublineages contributes to the understanding of the mechanism for the perpetuation and spread of H5N1, providing information that is directly relevant to control of the source of infection in poultry. It points to the necessity of surveillance that is geographically broader than previously supposed and that includes H5N1 viruses of greater genetic and antigenic diversity.
623 citations
TL;DR: The genome distribution of rice b HLH genes strongly supports the hypothesis that genome-wide and tandem duplication contributed to the expansion of the bHLH gene family, consistent with the birth-and-death theory of gene family evolution.
Abstract: The basic/helix-loop-helix (bHLH) transcription factors and their homologs form a large family in plant and animal genomes. They are known to play important roles in the specification of tissue types in animals. On the other hand, few plant bHLH proteins have been studied functionally. Recent completion of whole genome sequences of model plants Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) allows genome-wide analysis and comparison of the bHLH family in flowering plants. We have identified 167 bHLH genes in the rice genome, and their phylogenetic analysis indicates that they form well-supported clades, which are defined as subfamilies. In addition, sequence analysis of potential DNA-binding activity, the sequence motifs outside the bHLH domain, and the conservation of intron/exon structural patterns further support the evolutionary relationships among these proteins. The genome distribution of rice bHLH genes strongly supports the hypothesis that genome-wide and tandem duplication contributed to the expansion of the bHLH gene family, consistent with the birth-and-death theory of gene family evolution. Bioinformatics analysis suggests that rice bHLH proteins can potentially participate in a variety of combinatorial interactions, endowing them with the capacity to regulate a multitude of transcriptional programs. In addition, similar expression patterns suggest functional conservation between some rice bHLH genes and their close Arabidopsis homologs.
507 citations
TL;DR: A new chemosensor based on rhodamine B thiohydrazide was found to show a reversible dual chromo- and fluorogenic response toward Hg2+ in aqueous solution in a highly selective and sensitive manner.
354 citations
TL;DR: In this paper, the authors show that the continental shelves are a sink for atmospheric CO2 at mid-high latitudes (−0.33 Pg C a−1) and a source of CO 2 at low latitudes (0.11 PgC a −1).
Abstract: [1] In determining global sea-to-air CO2 flux from measurements or models, the ocean margin has not been resolved from the land or the open ocean. Recent studies have indicated that shelves can be either a large sink or a source for atmospheric CO2. This CO2 sink/source term may substantially alter our current view of the global carbon budget for land and oceans. However, past fieldwork and synthesis have focused on a few shelves in the northern temperate zone while the vast majority of other shelves are ignored. By dividing the highly heterogeneous shelves into seven provinces, we suggest that the continental shelves are a sink for atmospheric CO2 at mid-high latitudes (−0.33 Pg C a−1) and a source of CO2 at low latitudes (0.11 Pg C a−1). Warm temperature and high terrestrial organic carbon input are most likely responsible for the CO2 release in low latitude shelves.
327 citations
TL;DR: The main purpose of this work is to construct and analyze highly stable time discretizations which allow much larger time steps than those of a standard implicit-explicit approach.
Abstract: Numerical methods for solving the continuum model of the dynamics of the molecular beam epitaxy (MBE) require very large time simulation, and therefore large time steps become necessary. The main purpose of this work is to construct and analyze highly stable time discretizations which allow much larger time steps than those of a standard implicit-explicit approach. To this end, an extra term, which is consistent with the order of the time discretization, is added to stabilize the numerical schemes. Then the stability properties of the resulting schemes are established rigorously. Numerical experiments are carried out to support the theoretical claims. The proposed methods are also applied to simulate the MBE models with large solution times. The power laws for the coarsening process are obtained and are compared with previously published results.
320 citations
TL;DR: In the proposed system, antibodies immobilized on a solid substrate can interact with the corresponding antigens to form a composite substrate, which can capture reporter-labeled AgcoreAushell nanoparticles modified with the same antibodies.
Abstract: Layered core−shell bimetallic silver−gold nanoparticles were prepared by coating Au layers over Ag seeds by a seed-growth method. The composition of Ag100-xAux particles can vary from x = 0 to 30. TEM and SEM images clearly show that the bimetallic nanoparticles are of core−shell structure with some pinholes on the surface. Strong surface-enhanced Raman (SER) signals of thiophenol and p-aminothiophenol have been obtained with these colloids. It was found that the SERS activity of aggregated colloids critically depends on the molar ratio of Ag to Au. With the increase of the Au molar fraction, the SERS activity enhances first and then weakens, with the maximal intensity being 10 times stronger than that of Ag colloids. The AgcoreAushell nanoparticles were then labeled with monoclonal antibodies and SERS probes and used for immunoassay analysis. In the proposed system, antibodies immobilized on a solid substrate can interact with the corresponding antigens to form a composite substrate, which can capture re...
302 citations
TL;DR: In this paper, a multi-variable and multi-site approach was adopted for calibration and validation of the Soil Water Assessment Tool (SWAT) model for the Motueka catchment, making use of extensive field measurements.
Abstract: Many methods developed for calibration and validation of physically based distributed hydrological models are time consuming and computationally intensive. Only a small set of input parameters can be optimized, and the optimization often results in unrealistic values. In this study we adopted a multi-variable and multi-site approach to calibration and validation of the Soil Water Assessment Tool (SWAT) model for the Motueka catchment, making use of extensive field measurements. Not only were a number of hydrological processes (model components) in a catchment evaluated, but also a number of subcatchments were used in the calibration. The internal variables used were PET, annual water yield, daily streamflow, baseflow, and soil moisture. The study was conducted using an 11-year historical flow record (1990–2000); 1990–94 was used for calibration and 1995–2000 for validation. SWAT generally predicted well the PET, water yield and daily streamflow. The predicted daily streamflow matched the observed values, with a Nash–Sutcliffe coefficient of 0·78 during calibration and 0·72 during validation. However, values for subcatchments ranged from 0·31 to 0·67 during calibration, and 0·36 to 0·52 during validation. The predicted soil moisture remained wet compared with the measurement. About 50% of the extra soil water storage predicted by the model can be ascribed to overprediction of precipitation; the remaining 50% discrepancy was likely to be a result of poor representation of soil properties. Hydrological compensations in the modelling results are derived from water balances in the various pathways and storage (evaporation, streamflow, surface runoff, soil moisture and groundwater) and the contributions to streamflow from different geographic areas (hill slopes, variable source areas, sub-basins, and subcatchments). The use of an integrated multi-variable and multi-site method improved the model calibration and validation and highlighted the areas and hydrological processes requiring greater calibration effort. Copyright © 2005 John Wiley & Sons, Ltd.
237 citations
TL;DR: In this paper, the authors considered a time fractional diffusion equation on a finite domain and proposed a computationally effective implicit difference approximation (IDA) method to solve the problem, and proved that the IDA is unconditionally stable and convergent with O(tau+h^2) time and space steps.
Abstract: In this paper, we consider a time fractional diffusion equation on a finite domain. The equation is obtained from the standard diffusion equation by replacing the first-order time derivative by a fractional derivative (of order $0<\alpha<1$ ). We propose a computationally effective implicit difference approximation to solve the time fractional diffusion equation. Stability and convergence of the method are discussed. We prove that the implicit difference approximation (IDA) is unconditionally stable, and the IDA is convergent with $O(\tau+h^2)$, where $\tau$ and $h$ are time and space steps, respectively. Some numerical examples are presented to show the application of the present technique.
236 citations
TL;DR: In this paper, the evidential reasoning (ER) approach was extended to model new types of uncertainties including interval belief degrees and interval data that could be incurred in decision situations such as group decision making.
233 citations
TL;DR: Their structural differences were investigated using crystal structure analysis, revealing that the influence of steric hindrance of organic ligand on the structures of Keggin-based coordination polymers is realized through changing the number of metal-organic units surrounding the POM anion.
Abstract: Five Keggin-based 3D coordination polymers, namely, [Cu3(pz)3(PW12O40)] (pz = pyrazine) (1), [Cu3(2,3-Me2pz)3(PW12O40)] (2,3-Me2pz = 2,3-dimethylpyrazine) (2), [Cu2(2,5-Me2pz)1.5(2,5-HMe2pz)(PW12O40)] (2,5-Me2pz = 2,5-dimethylpyrazine) (3), [Cu3(2,3-Me2pz)3(PMo12O40)] (4), and [Ag3(pz)3(PW12O40)]·0.5H2O (5), were synthesized and structurally characterized. Crystal data are as follows: trigonal, space group R3c, a = 18.4070(14) A, c = 22.544(3) A, γ = 120°, and Z = 6 for 1; orthorhombic, space group Pccn, a = 16.599(2) A, b = 20.470(3) A, c = 14.3757(18) A, and Z = 4 for 2; triclinic, space group P1, a = 10.667(2) A, b = 11.147(2) A, c = 20.207(4) A, α = 90.983(4)°, β = 108.128(3)°, γ = 92.150(4)°, and Z = 2 for 3; orthorhombic, space group Pccn, a = 16.450(3) A, b = 20.170(4) A, c = 14.244(3) A, and Z = 4 for 4; and rhombohedral, space group R32, a = 18.2047(13) A, c = 23.637(3) A, γ = 120°, and Z = 6 for 5. Their structural differences were investigated using crystal structure analysis, revealing that...
231 citations
TL;DR: The data revealed that curcumin could significantly inhibit the growth and induce apoptosis in Ho‐8910 cells, suggesting that these activities may contribute to the anticarcinogenic action ofCurcumin.
TL;DR: In this article, the authors examined dissolved oxygen (DO), the carbonate system and nutrients in the upper reach of the Pearl River estuary in a very dry season in February of 2004.
TL;DR: In this paper, a novel oriented TiO2 nanotube array on Ti substrate was fabricated by using an electrochemical method, and the structure and surface morphology of the array was examined by Raman spectroscopy and scanning electronic microscopy, respectively.
Abstract: bNational Institute of Standards and Technology, Gaithersburg, Maryland 20899-8621, USA A novel oriented TiO2 nanotube TN array on Ti substrate was fabricated by using an electrochemical method. The structure and surface morphology of the TN array was examined by Raman spectroscopy and scanning electronic microscopy, respectively. The photocatalytic activity of the TN arrays was evaluated by the removal of methylene blue in aqueous solution. The effects of structure and morphology of the TN array on its photocatalytic activity were investigated. It was observed that the crystal structure, morphologies, and nanotube sizes were greatly influenced by anodization voltage and calcination temperature. The shift of absorption edges shorter wavelengths were ascribed to the quantum effect of the tube wall thickness. The TN arrays prepared at 20 V and calcined at 450°C have the highest photocatalytic activity due to an increase in the anatase crystal phase and an increase in surface area. When the calcination temperature was higher than 450°C, the photocatalytic activity of the TN array decreased, which was ascribed to excessive rutile content and a decrease in surface area resulting from the sintering and growth of TiO2 crystallites.
TL;DR: A general and efficient FeCl3-catalyzed substitution reaction of propargylic alcohols with carbon- and heteroatom-centered nucleophiles such as allyl trimethylsilane, alcohols, aromatic compounds, thiols, and amides, leading to the construction of C-C, C-O,C-S and C-N bonds has been developed.
Abstract: A general and efficient FeCl3-catalyzed substitution reaction of propargylic alcohols with carbon- and heteroatom-centered nucleophiles such as allyl trimethylsilane, alcohols, aromatic compounds, thiols, and amides, leading to the construction of C−C, C−O, C−S and C−N bonds, has been developed.
TL;DR: A combined surface-enhanced Raman spectroscopy (SERS) and break junction method to detect and characterize molecules between two microfabricated electrodes separated with a gap that can be continuously adjusted from a few angstroms to nanometers is developed.
Abstract: We have developed a combined surface-enhanced Raman spectroscopy (SERS) and break junction method to detect and characterize molecules between two microfabricated electrodes separated with a gap that can be continuously adjusted from a few angstroms to nanometers. It allows us to obtain a vibrational fingerprint of the adjustable molecular junction while performing electron transport measurements on the molecule simultaneously. This new approach will provide not only new insights into electron transport properties of molecule junctions on a chip but also the mechanism of single-molecule-SERS.
TL;DR: A dual fluorescent charge transfer fluoroionophore with its ionophore incorporated in the electron acceptor was developed and was found to show a highly selective fluorescent response to Cu2+ with a dramatic enhancement in its CT emission.
TL;DR: A dinuclear complex, [(CoTPA)2(DHBQ)](PF6)3, has been successfully synthesized that exhibits a valence tautomeric transition with a distinct hysteresis effect (13 K) around room temperature and photoinduced valencetautomerism under low temperature.
Abstract: A dinuclear complex, [(CoTPA)2(DHBQ)](PF6)3, has been successfully synthesized that exhibits a valence tautomeric transition with a distinct hysteresis effect (13 K) around room temperature and photoinduced valence tautomerism under low temperature.
TL;DR: LiNi 0.8 Co 0.2 O 2 cathode material showed a performance loss after storage in air as discussed by the authors, and the surface species on the material formed during the exposure to air were identified through TG, SEM, TPD-MS, XRD and XPS.
TL;DR: Crystal structural analysis reveals that the relationship between the size of the void of the 2D network and that of POMs is of key importance for successful synthesis of Poms-based open metal-organic frameworks.
Abstract: A series of polyoxometalates (POMs)-based coordination polymers, namely, {[Cu(2,3-Me2pz)(2,5-Me2pz)0.5]4(SiW12O40)(2,5-Me2pz)}n (2,3-Me2pz = 2,3-dimethylpyrazine; 2,5-Me2pz = 2,5-dimethylpyrazine; 1), {[Cu2(4,4‘-bipy)4(H2O)4](SiW12O40)(H2O)18}n (4,4‘-bipy = 4,4‘-bipyridine; 2), {[Cu(2-Mepz)1.5]3(PMo12O40)(H2O)3.5}n (2-Mepz = 2-methylpyrazine; 3), {[Ag(2,3-Me2pz)1.5]4(SiW12O40)}n (4), {[Cu(pz)1.5]4(SiW12O40)(H2O)3}n (pz = pyrazine; 5), {[Cu(2,3-Me2pz)1.5]4(SiW12O40)}n (6), {[Cu(4,4‘-bipy)1.75]4(SiW12O40)(H2O)2}n (7), and {[Cu2(4,4‘-bipy)4(H2O)4](SiW12O40)(4,4‘-bipy)2(H2O)4}n (8), were synthesized through direct incorporation between POMs and the voids of the 2D network. Crystal structural analysis reveals that the relationship between the size of the void of the 2D network and that of POMs is of key importance for successful synthesis of POMs-based open metal−organic frameworks. Guest replacement shows that the pore size of the framework constructed through direct incorporation between POMs and the voids o...
TL;DR: In this paper, the surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process.
TL;DR: It is shown that Axin activates TGF‐β signaling by forming a multimeric complex consisting of Smad7 and ubiquitin E3 ligase Arkadia, and coexpression of Wnt‐1 reduced Smad 7 ubiquitination by downregulating Axin levels, underscoring the importance of Axin as an intrinsic regulator in TGF-β signaling.
Abstract: TGF-β signaling involves a wide array of signaling molecules and multiple controlling events. Scaffold proteins create a functional proximity of signaling molecules and control the specificity of signal transduction. While many components involved in the TGF-β pathway have been elucidated, little is known about how those components are coordinated by scaffold proteins. Here, we show that Axin activates TGF-β signaling by forming a multimeric complex consisting of Smad7 and ubiquitin E3 ligase Arkadia. Axin depends on Arkadia to facilitate TGF-β signaling, as their small interfering RNAs reciprocally abolished the stimulatory effect on TGF-β signaling. Specific knockdown of Axin or Arkadia revealed that Axin and Arkadia cooperate with each other in promoting Smad7 ubiquitination. Pulse-chase experiments further illustrated that Axin significantly decreased the half-life of Smad7. Axin also induces nuclear export of Smad7. Interestingly, Axin associates with Arkadia and Smad7 independently of TGF-β signal, in contrast to its transient association with inactive Smad3. However, coexpression of Wnt-1 reduced Smad7 ubiquitination by downregulating Axin levels, underscoring the importance of Axin as an intrinsic regulator in TGF-β signaling.
TL;DR: The molecular and cellular properties of two types of niche, namely the osteoblastic and the vascular niche, in homeostatic regulation of HSC behavior, including its maintenance, proliferation, differentiation, mobilization and homing are summarized.
TL;DR: A novel single-chain magnet, [MnIII3O(Meppz)3(EtOH)4(OAc)] has been successfully synthesized from a secondary building block with an S = 1 ground state that exhibits both magnetization relaxation and dielectric relaxation properties.
Abstract: A novel single-chain magnet, [MnIII3O(Meppz)3(EtOH)4(OAc)] (1), has been successfully synthesized from a secondary building block [MnIII3O(Meppz)3(EtOH)5Cl] (2) with an S = 1 ground state. SCM 1 exhibits both magnetization relaxation and dielectric relaxation properties.
TL;DR: It is shown both analytically and numerically that stability switches of interior equilibrium may occur as maturation time delay increases: stability may change from stable to unstable to finally stable, implying that a large delay can be stabilizing.
Abstract: We formulate and study a robust stage structured predator-prey model of Beddington- DeAngelis-type functional response The time delay is the time taken from birth to maturity The Beddington-DeAngelis functional response is similar to the Holling type 2 functional response but contains an extra term describing mutual interference by predators First we show that the predator coexists with prey permanently if and only if the predator's recruitment rate at the peak of prey abundance is larger than its death rate Second, we show that if the system is permanent, then a sufficiently large degree of the predator interference can not only stabilize the system but also guarantee the stability of the system against the increase of the carrying capacity of prey and the increase of birth rate of the adult predator Third, we show both analytically and numerically that stability switches of interior equilibrium may occur as maturation time delay increases: stability may change from stable to unstable to finally stable, implying that a large delay can be stabilizing
TL;DR: In this article, it was shown that the energy released by neutrino annihilation is sufficient for gamma-ray bursts when the contribution from the optically thick region of the flow is included.
Abstract: We first refine the fixed concept in the literature that the usage of the Newtonian potential in studies of black hole accretion is invalid and the general relativistic effect must be considered. As our main results, we then show that the energy released by neutrino annihilation in neutrino-dominated accretion flows is sufficient for gamma-ray bursts when the contribution from the optically thick region of the flow is included, and that in the optically thick region advection does not necessarily dominate over neutrino cooling because the advection factor is relevant to the geometrical depth rather than the optical depth of the flow.
TL;DR: In this paper, the photoactivity of the Ni catalyst for H 2 evolution was investigated in the presence of methanol sacrificial reagent under visible light illumination and the experimental results were rationalized by assuming that MWNTs serve as photosensitizer, synergetic with metallic Ni, greatly enhancing the activity of visible light-responsive photocatalyst.
TL;DR: In this paper, the use of attenuated total reflectance infrared spectroscopy (MIR-ATR) and fiber optic diffuse reflectance near infrared (FODR-NIR) as rapid and cost-efficient classification and quantification techniques for the authentication of camellia oils have been preliminarily investigated.
TL;DR: In this article, five Keggin-based metal complexes, [Ag3(2,4‘-bipy)3PMo12O40] (1), [Ag4(2.4 ǫ-bippy)4SiW12O42] (2), Ag3( 2.4 bipy )4PW12 o42] [3] (3), [Cu4( 2,4´bipyi)4Pw12 o40] [4] (4), and [Cu3(
Abstract: Five Keggin-based metal complexes, [Ag3(2,4‘-bipy)3PMo12O40] (1), [Ag4(2,4‘-bipy)4SiW12O40] (2), [Ag3(2,4‘-bipy)4PW12O40] (3), [Cu4(2,4‘-bipy)4SiW12O40] (4), and [Cu3(2,4‘-bipy)4PW12O40] (5) (2,4‘-bipy = 2,4‘-bipyridine), were synthesized and structurally characterized. Among them, complexes 1, 2, and 4 show a cyclic structure, while complexes 3 and 5 exhibit a one-dimensional (1D) chain structure. Investigation of their structural differences reveals that anions play a key role in the formation of a cyclic structure.