Showing papers by "Shanghai University published in 2006"

Efficient Steganographic Embedding by Exploiting Modification Direction

Abstract: A novel method of steganographic embedding in digital images is described, in which each secret digit in a (2n+1)-ary notational system is carried by n cover pixels and, at most, only one pixel is increased or decreased by 1. In other words, the (2n+1) different ways of modification to the cover pixels correspond to (2n+1) possible values of a secret digit. Because the directions of' modification are fully exploited, the proposed method provides high embedding efficiency that is better than previous techniques

The Rice Tapetum Degeneration Retardation Gene Is Required for Tapetum Degradation and Anther Development

Abstract: In flowering plants, tapetum degeneration is proposed to be triggered by a programmed cell death (PCD) process during late stages of pollen development; the PCD is thought to provide cellular contents supporting pollen wall formation and to allow the subsequent pollen release. However, the molecular basis regulating tapetum PCD in plants remains poorly understood. We report the isolation and characterization of a rice (Oryza sativa) male sterile mutant tapetum degeneration retardation (tdr), which exhibits degeneration retardation of the tapetum and middle layer as well as collapse of microspores. The TDR gene is preferentially expressed in the tapetum and encodes a putative basic helix-loop-helix protein, which is likely localized to the nucleus. More importantly, two genes, Os CP1 and Os c6, encoding a Cys protease and a protease inhibitor, respectively, were shown to be the likely direct targets of TDR through chromatin immunoprecipitation analyses and the electrophoretic mobility shift assay. These results indicate that TDR is a key component of the molecular network regulating rice tapetum development and degeneration.

Genome-Wide Analysis of Basic/Helix-Loop-Helix Transcription Factor Family in Rice and Arabidopsis

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.

Hydrothermal synthesis and gas sensing characters of ZnO nanorods

Abstract: ZnO nanorods are prepared by a hydrothermal process with cetyltrimethylammonium bromide (CTAB) and zinc powder at 182 °C. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The gas sensing properties of the materials have been investigated. The results indicate that the as-prepared ZnO nanorods show much better sensitivity and stability than the conventional materials. The PdO doping can improve the sensitivity and selectivity of the sensors. ZnO nanorods are excellent potential candidates for gas sensors.

Hairy Root and Its Application in Plant Genetic Engineering

Abstract: Agrobacterium rhizogenes Conn. causes hairy root disease in plants. Hairy root-infected A. rhizogenes is characterized by a high growth rate and genetic stability. Hairy root cultures have been proven to be an efficient means of producing secondary metabolites that are normally biosynthesized in roots of differentiated plants. Furthermore, a transgenic root system offers tremendous potential for introducing additional genes along with the Ri plasmid, especially with modified genes, into medicinal plant cells with A. rhizogenes vector systems. The cultures have turned out to be a valuable tool with which to study the biochemical properties and the gene expression profile of metabolic pathways. Moreover, the cultures can be used to elucidate the intermediates and key enzymes involved in the biosynthesis of secondary metabolites. The present article discusses various applications of hairy root cultures in plant genetic engineering and potential problems associated with them. (Managing editor: Wei Wang)

Chinese red yeast rice (Monascus purpureus) for primary hyperlipidemia. A meta-analysis of randomized controlled trials

Abstract: Extracts of Chinese red yeast rice (RYR, a traditional dietary seasoning of Monascus purpureus) contains several active ingredients including lovastatin, and several trials of its possible lipid-lowering effects have been conducted. This meta-analysis assesses the effectiveness and safety of RYR preparations on lipid modification in primary hyperlipidemia. We included randomized controlled trials testing RYR preparation, compared with placebo, no treatment, statins, or other active lipid-lowering agents in people with hyperlipidemia through searching PubMed, CBMdisk, TCMLARS, the Cochrane Library, and AMED up to December 2004. Ninety-three randomized trials (9625 participants) were included and three RYR preparations (Cholestin, Xuezhikang and Zhibituo) were tested. The methodological quality of trial reports was generally low in terms of generation of the allocation sequence, allocation concealment, blinding, and intention-to-treat. The combined results showed significant reduction of serum total cholesterol levels (weighted mean difference -0.91 mmol/L, 95% confidence interval -1.12 to -0.71), triglycerides levels (-0.41 mmol/L, -0.6 to -0.22), and LDL-cholesterol levels (-0.73 mmol/L, -1.02 to -0.043), and increase of HDL-cholesterol levels (0.15 mmol/L, 0.09 to 0.22) by RYR treatment compared with placebo. The lipid modification effects appeared to be similar to pravastatin, simvastatin, lovastatin, atorvastatin, or fluvastatin. Compared with non-statin lipid lowering agents, RYR preparations appeared superior to nicotinate and fish oils, but equal to or less effective than fenofibrate and gemfibrozil. No significant difference in lipid profile was found between Xuezhikang and Zhibituo. RYR preparations were associated with non-serious adverse effects such as dizziness and gastrointestinal discomfort. Current evidence shows short-term beneficial effects of RYR preparations on lipid modification. More rigorous trials are needed, and long-term effects and safety should be investigated if RYR preparations are to be recommended as one of the alternative treatments for primary hyperlipidemia.

Chaos synchronization of the Chua system with a fractional order

Abstract: Chaos synchronization of two identical Chua systems with the same fractional order is studied by utilizing the Pecora–Carroll (PC) method, the active–passive decomposition (PAD) method, the one-way coupling method and the bidirectional coupling one. The sufficient conditions for achieving synchronization between these two systems are derived via the Laplace transformation theory. Numerical simulations show the effectiveness of the theoretical analyses.

Anti-influenza agents from plants and traditional Chinese medicine.

Abstract: Influenza is a serious threat to health in all parts of the world. The control and treatment of influenza depends mainly on chemical or biochemical agents and, to date, some anti-influenza agents have been isolated from plants as a result of chemical and pharmacological studies. These agents include a variety of polyphenols, flavonoids, saponins, glucosides and alkaloids. Traditional medicine focuses on the use of herbs and traditional Chinese medicine has performed well in clinical practice and shows a potential in the therapy of influenza and its symptoms. The present paper reviews some constituents and extracts from plants and traditional Chinese medicine with anti-influenza activity.

Measurements of emission factors for primary carbonaceous particles from residential raw-coal combustion in China

Abstract: [1] The emission factors (EFs) of particles and their carbonaceous fractions, including black carbon (BC) and organic carbon (OC), are measured for residential burning of coal-chunks. Nine types of coals with wide-ranged thermal maturities were used. Particulate emissions from coal-stove are collected on quartz fiber filters through a dilution sampling system and analyzed for BC and OC by thermal-optical method. The EFs of particulate matter, OC, and BC from bituminous coal burning are 16.77, 8.29, and 3.32 g/kg, respectively, on the basis of burned dry and ash-free (daf) coal mass. They were much higher than those of anthracites, which are 0.78, 0.04, and 0.004 g/kg, respectively. Annual emission inventories of particles, OC, and BC from household coal burning are also estimated based on the EFs and coal consumption. The results of the calculations are 917.8, 477.7, and 128.4 gigagrams (Gg) for total particles, OC, and BC emitted in China during the year 2000.

Hydrothermal synthesis of In2O3 for detecting H2S in air

Abstract: Nanocrystalline In 2 O 3 gas sensing material was prepared by sintering a precursor In(OH) 3 at 600 °C which was hydrothermally synthesized at 250 °C for 24 h by using InCl 3 ·4H 2 O as a starting material The nanopowder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry–differential scanning calorimetry (TG–DSC) and X-ray photoelectron spectrometer (XPS) The results indicated that the precursor of indium oxide was cubic indium hydroxide with range size of 50–80 nm, and indium oxide was composed of In and O Gas sensing properties of the sensors were tested by mixing a gas in air at static state, the tested results showed that the sensor based on In 2 O 3 nanocrystals had satisfying H 2 S gas sensing properties at rather low temperature

Binary Ni-Nb bulk metallic glasses

Abstract: We studied the glass forming ability of Ni–Nb binary alloys and found that some of the alloys can be prepared into bulk metallic glasses by a conventional Cu-mold casting. The best glass former within the compositional range studied is off-eutectic Ni62Nb38 alloy, which is markedly different from those predicted by the multicomponent and deep eutectic rules. The glass formation mechanism for binary Ni–Nb alloys was studied from the thermodynamic point of view and a parameter γ* was proposed to approach the ability of glass formation against crystallization.

Boundary element‐free method (BEFM) and its application to two‐dimensional elasticity problems

Abstract: In this Study, we first discuss the moving least-square approximation (MLS) method. In some cases, the MLS may form an ill-conditioned system of equations so that the Solution cannot be correctly obtained. Hence, in this paper, we propose an improved moving least-square approximation (IMLS) method. In the IMLS method, the orthogonal function system with a weight function is used as the basis function. The IMLS has higher computational efficiency and precision than the MLS, and will not lead to an ill-conditioned system of equations. Combining the boundary integral equation (BIE) method and the IMLS approximation method, a direct meshless BIE method, the boundary element-free method (BEFM), for two-dimensional elasticity is presented. Compared to other meshless BIE methods, BEFM is a direct numerical method in which the basic unknown quantity is the real solution of the nodal variables, and the boundary conditions can be applied easily; hence, it has higher computational precision. For demonstration purpose, selected numerical examples are given. Copyright (c) 2005 John Wiley & Sons, Ltd.

Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machines

Abstract: In this paper, pulsating torque components of permanent magnet machines and pulsating torque minimization techniques are discussed for axial flux surface-magnet disc-type PM machines. The pulsating torque analysis describing general instantaneous electromagnetic torque equation and torque ripple factor is briefly provided in order to analyze torque ripple component. Detailed finite-element analyses focusing on the minimization of cogging and torque ripple components using several techniques are also given. A detailed comparison of the two techniques is also illustrated in this paper.

Predicting protein-protein interactions from sequences in a hybridization space

Abstract: To understand the networks in living cells, it is indispensably important to identify protein−protein interactions on a genomic scale Unfortunately, it is both time-consuming and expensive to do so solely based on experiments due to the nature of the problem whose complexity is obviously overwhelming, just like the fact that “life is complicated” Therefore, developing computational techniques for predicting protein−protein interactions would be of significant value in this regard By fusing the approach based on the gene ontology and the approach of pseudo-amino acid composition, a predictor called “GO-PseAA” predictor was established to deal with this problem As a showcase, prediction was performed on 6323 protein pairs from yeast To avoid redundancy and homology bias, none of the protein pairs investigated has ≥40% sequence identity with any other The overall success rate obtained by jackknife cross-validation was 816%, indicating the GO-PseAA predictor is very promising for predicting protein−pro

Ferroelectric and piezoelectric properties of (Na, K)0.5Bi0.5TiO3 lead free ceramics

Abstract: (1 − x)Na0.5Bi0.5TiO3 − xK0.5Bi0.5TiO3 (NKBT100x; x being the mole ratio) piezoelectric ceramics were prepared by a conventional solid reaction method. The microstructure and ferroelectric properties of NKBT100x solid solution ceramics with compositions of Na0.5Bi0.5TiO3 (NBT)-rich and K0.5Bi0.5TiO3 (KBT)-rich were investigated by SEM, XRD, temperature dependence of dielectric constant, and hysteresis loop, respectively. XRD studies showed that the pure perovskite structure existed in NKBT100x ceramics with x ≤ 0.50, while a small amount of a second phase, K4Ti3O8, appeared in the ceramics with x ≥ 0.70 due to the structural instability of KBT-rich ceramics. The grain size decreased with increasing KBT content, showing that the KBT-rich solid solutions were very difficult to densify fully. The temperature dependence of the dielectric constant of NKBT100x ceramics showed that the depolarization temperature (Td) reached a minimum value at the composition of x = 0.16 (NKBT16) near the morphotropic phase boundary, which suggested that the ferroelectric state of co-existence between the rhombohedral phase of NBT and tetragonal phase of KBT were not as stable as the single phase of NBT and KBT, respectively. The poled density NKBT50 (x = 0.50) showed high piezoelectric properties, high Td and low dielectric loss, which was a good candidate for lead free piezoelectric ceramics working at relatively high temperatures.

Enlargement of Gold Nanoparticles on the Surface of a Self-Assembled Monolayer Modified Electrode: A Mode in Biosensor Design

Abstract: Gold nanoparticle (Au-NP) seeds were adsorbed onto the surface of a self-assembled monolayer (SAM)-modified electrode. With the treatment of this modified electrode by Au-NPs growth solution containing different concentrations of H2O2 or cholesterol along with cholesterol oxidase (ChOx), the Au-NP seeds on the electrode surface were enlarged in varying degrees. As a result, the peak currents in corresponding cyclic voltammograms were inversely proportional to the concentration of H2O2 or cholesterol. ChOx was also further modified onto the surface of Au/SAM/Au-NP electrode to prepare Au/SAM/Au-NP/ChOx electrode. Using the enzyme-modified electrode to detect cholesterol, which also utilized the enlargement of the NPs, an extraordinary low detection limit of 5 × 10-9 M was achieved and two linear dependence ranges of 7.5 × 10-8−1 × 10-6 and 1 × 10-6−5 × 10-5 M were obtained. Consequently, new kinds of H2O2 and cholesterol biosensors could be fabricated.

A new method to realize cluster synchronization in connected chaotic networks

Abstract: In this article, a new method, which constructs a coupling scheme with cooperative and competitive weight-couplings, is used to stabilize arbitrarily selected cluster synchronization patterns with several clusters for connected chaotic networks. By the coupling scheme, a sufficient condition about the global stability of the selected cluster synchronization patterns is derived. That is to say, when the sufficient condition is satisfied, arbitrarily selected cluster synchronization patterns in connected chaotic networks can be achieved via an appropriate coupled scheme. The effectiveness of the method is illustrated by an example.

Optimal lot solution to cardinality constrained mean–variance formulation for portfolio selection

Abstract: The pioneering work of the mean–variance formulation proposed by Markowitz in the 1950s has provided a scientific foundation for modern portfolio selection. Although the trade practice often confines portfolio selection with certain discrete features, the existing theory and solution methodologies of portfolio selection have been primarily developed for the continuous solution of the portfolio policy that could be far away from the real integer optimum. We consider in this paper an exact solution algorithm in obtaining an optimal lot solution to cardinality constrained mean–variance formulation for portfolio selection under concave transaction costs. Specifically, a convergent Lagrangian and contour-domain cut method is proposed for solving this class of discrete-feature constrained portfolio selection problems by exploiting some prominent features of the mean–variance formulation and the portfolio model under consideration. Computational results are reported using data from the Hong Kong stock market.

Fundamental Principles That Govern Retrofitting of Reinforced Concrete Columns by Steel and FRP Jacketing

Abstract: Extensive investigations on seismic retrofitting of reinforced concrete columns have been undertaken in recent years and many retrofitting methods have been developed and reported in the literature. However contradictory results and conclusions are not rare especially for jacketing of rectilinear columns, and there is not a clear picture on the current state-of-the-art in the literature. This work is based on the review and assessment of more than 120 papers, and collection and analysis of more than 700 column tests. In combination with the authors' original theoretical studies and experimental testing, this work identifies the key factors that affect the effectiveness and deficiencies of different retrofitting techniques and provides engineers with a clearer picture on the capabilities of different retrofitting techniques, in particular how to improve the effectiveness of a jacketing system. From the theoretical studies, this work also provides researchers with fundamental insight and principles that gov...

Synthesis of dual-band bandpass filters using successive frequency transformations and circuit conversions

Abstract: A novel method is proposed to synthesize dual-band bandpass filters (BPFs) from a prototype low-pass filter. By implementing successive frequency transformations and circuit conversions, a new filter topology is obtained which consists of only admittance inverters and series resonators, and is thereby easy to be realized by using conventional distributed elements. A dual-band BPF with center frequencies of 1.8GHz and 2.4GHz is designed and fabricated using microstrip lines and stubs. The simulated and measured results show a good agreement and validate the proposed theory.

Synchronization of complex dynamical networks with time delays

Abstract: In the present paper, two kinds of dynamical complex networks are considered. The first is that elements of every node have different time delays but all nodes in such networks have the same time-delay vector. The second is that different nodes have different time-delay vectors, and the elements of each node also have different time delays. Corresponding synchronization theorems are established. Numerical examples show the efficiency of the derived theorems.