4,092 research outputs found
Identification of non-Gaussian parametric model with time-varying coefficients using wavelet basis
Many time series in practice turn to be the time-varying (TV) non-Gaussian processes. In this paper, we address the problem of how to describe these non-stationary non-Gaussian time series. A non-Gaussian AR model with TV parameters is proposed to track the non-stationary non-Gaussian characteristics of the signal. Since wavelet has flexibility in capturing the signal's transient characteristics at different scales, a set of wavelet basis is employed so that the model parameters can effectively track the variations of TV signals and be used to estimate the corresponding TV bispectrum. The experiments results confirm the superior performance of the presented model over the previous method.published_or_final_versio
Identification of non-Gaussian parametric model with time-varying coefficients using wavelet basis
Many time series in practice turn to be the time-varying (TV) non-Gaussian processes. In this paper, we address the problem of how to describe these non-stationary non-Gaussian time series. A non-Gaussian AR model with TV parameters is proposed to track the non-stationary non-Gaussian characteristics of the signal. Since wavelet has flexibility in capturing the signal's transient characteristics at different scales, a set of wavelet basis is employed so that the model parameters can effectively track the variations of TV signals and be used to estimate the corresponding TV bispectrum. The experiments results confirm the superior performance of the presented model over the previous method.published_or_final_versio
Expression and functional analysis of apoptosis-related gene BmICAD in silkworm, Bombyx mori
The ICAD gene plays an important role in the growth and development processes in insects. We conducted a molecular cloning and functional analysis to study a specific silkworm gene BmICAD related to apoptosis. The BmICAD gene was obtained from the fifth instar larvae of the silkworm by RTPCR and over-expressed in Escherichia coli as His-tagged fusion proteins. Subcellular localization of the protein indicated that BmICAD was found in the cytoplasm near the nucleus. RNAi assay indicated that the apoptosis rate of Bm5 cells increased markedly. A His pull-down assay was used to investigate proteins that bind to rBmICAD. Two proteins, DNA supercoiling factor (SCF) and secreted protein acidic and rich in cysteine (SPARC), were found. These results indicate that down regulation of BmICAD can increase the apoptosis rate of Bm5 cells, and that SCF and SPARC may have important roles by interacting with BmICAD during this process.Key words: Bombyx mori, BmICAD, subcellular localization, RNAi, protein interaction
Molecular characterization of Cymbidium kanran cultivars based on extended random amplified polymorphic DNA (ERAPD) markers
Fifty-four Cymbidium kanran cultivars from China, Japan and Korea were examined and analyzed by using the successive screening of 3'-end extended random primer amplified polymorphic DNA (ERAPD) markers to determine their molecular diversity and relationships. In ERAPD analyses, the strandspecific DNA sequence of direct oligonucleotide extension sequencing primers was independently read from each of the RAPD fragments without recourse to cloning or strand separation. Eight primers, identified from 80 original RAPD primers, produced strong repetitive polymorphic bands that were used in 3'-end-extended random primer amplified DNA marker analysis. The products of primers ACTGAACGCCCG + ACTGAACGCCGG and ACTGAACGCCC + ACTGAACGCC, linked to the same locus (2.5 - kb), were developed from the original ACTGAACGC RAPD primer; the products of this marker were more stable and specific than the original RAPD marker. Unweighted pair-group mean analysis (UPGMA) grouped them into two clusters based upon geographical traits. We demonstrated that the ERAPD technique is a powerful tool for cultivar identification and establishment of genetic relationships of cultivars in Cymbidium kanran.Key words: Cymbidium kanran; genetic relationship; Extended random amplified polymorphic DNA (ERAPD
Rapid genetic transformation of sweetpotato (Ipomoea batatas (L.) Lam) via organogenesis
An efficient and rapid Agrobacterium-mediated transformation method based on de novo (via callus) organogenesis has been developed from petioles with leaf for sweetpotato (Ipomoea batatas (L.) Lam). Stable transgenic sweetpotato plants cv. Jewel were obtained in six to ten weeks after infection with Agrobacterium tumefaciens hyper-virulent strain EHA105 harboring a binary vector pCIP45 bearing the nptII gene conferring resistance to kanamycin and a gene of interest. PCR and Southern analyses confirmed stable integration of both genes into the sweetpotato genome. The expression of the nptII gene was assessed by reverse-transcribed PCR and callus development in a high kanamycin medium. A two-step organogenesis regeneration using media containing 4-fluorophenoxyacetic acid (4-FA) and zeatin was used in two independent transformation experiments yielding 20% and 10% transformation efficiency, respectively. When using indolacetic acid (IAA) in regeneration media, the transformation efficiency dropped to 4.0%. It indicated an auxin to cytokinin treatment could improve the regeneration of transgenic calluses. This rapid organogenesis-based transformation strategy represents an important improvement over existing methods and will facilitate producing large-scale transgenic sweetpotato plants the genetic improvement of a crop that is reputed to be difficult to transform
Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers
Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECM’s major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure
Reducing Health Risks from Indoor Exposures in Rapidly Developing Urban China.
Background: Over the past two decades there has been a large migration of China’s population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly. Objectives: We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants. Discussion: As documented by China’s Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population’s exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building’s initial design. Conclusions: Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health
Prediction of the functional class of metal-binding proteins from sequence derived physicochemical properties by support vector machine approach
Metal-binding proteins play important roles in structural stability, signaling, regulation, transport, immune response, metabolism control, and metal homeostasis. Because of their functional and sequence diversity, it is desirable to explore additional methods for predicting metal-binding proteins irrespective of sequence similarity. This work explores support vector machines (SVM) as such a method. SVM prediction systems were developed by using 53,333 metal-binding and 147,347 non-metal-binding proteins, and evaluated by an independent set of 31,448 metal-binding and 79,051 non-metal-binding proteins. The computed prediction accuracy is 86.3%, 81.6%, 83.5%, 94.0%, 81.2%, 85.4%, 77.6%, 90.4%, 90.9%, 74.9% and 78.1% for calcium-binding, cobalt-binding, copper-binding, iron-binding, magnesium-binding, manganese-binding, nickel-binding, potassium-binding, sodium-binding, zinc-binding, and all metal-binding proteins respectively. The accuracy for the non-member proteins of each class is 88.2%, 99.9%, 98.1%, 91.4%, 87.9%, 94.5%, 99.2%, 99.9%, 99.9%, 98.0%, and 88.0% respectively. Comparable accuracies were obtained by using a different SVM kernel function. Our method predicts 67% of the 87 metal-binding proteins non-homologous to any protein in the Swissprot database and 85.3% of the 333 proteins of known metal-binding domains as metal-binding. These suggest the usefulness of SVM for facilitating the prediction of metal-binding proteins. Our software can be accessed at the SVMProt server
The TOC-Based Algorithm for Solving Multiple Constraint Resources: a Re-examination
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