1,033 research outputs found

    Automatic domain ontology extraction for context-sensitive opinion mining

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    Automated analysis of the sentiments presented in online consumer feedbacks can facilitate both organizations’ business strategy development and individual consumers’ comparison shopping. Nevertheless, existing opinion mining methods either adopt a context-free sentiment classification approach or rely on a large number of manually annotated training examples to perform context sensitive sentiment classification. Guided by the design science research methodology, we illustrate the design, development, and evaluation of a novel fuzzy domain ontology based contextsensitive opinion mining system. Our novel ontology extraction mechanism underpinned by a variant of Kullback-Leibler divergence can automatically acquire contextual sentiment knowledge across various product domains to improve the sentiment analysis processes. Evaluated based on a benchmark dataset and real consumer reviews collected from Amazon.com, our system shows remarkable performance improvement over the context-free baseline

    Information Granulation for the Design of Granular Information Retrieval Systems

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    With the explosive growth of the amount of information stored on computer networks such as the Internet, it is increasingly more difficult for information seekers to retrieve relevant information. Traditional document ranking functions employed by Internet search engines can be enhanced to improve the effectiveness of information retrieval (IR). This paper illustrates the design and development of a granular IR system to facilitate domain specific search. In particular, a novel computational model is designed to rank documents according the searchers’ specific granularity requirements. The initial experiments confirm that our granular IR system outperforms a classical vector-based IR system. In addition, user-based evaluations also demonstrate that our granular IR system is effective when compared with a well-known Internet search engine. Our research work opens the door to the design and development of the next generation of Internet search engines to alleviate the problem of information overload

    Pions in isospin asymmetric matter and nuclear Drell-Yan scattering

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    Using a self-consistent delta-hole model the pion propagation in isospin asymmetric nuclear matter is studied. In neutron-rich matter, corresponding to heavy nuclei, a significant difference in positive and negative pion light-cone distributions is obtained leading to a nuclear enhancement of up antiquark distribution compared to the down antiquark one. This means that the sea-quark asymmetry in the free nucleon cannot be extracted model independently from an experiment on a neutron-rich nucleus.Comment: 10 pages, 3 figures (included), Latex 2.09, uses elsart.sty, epsf.st

    Arginine-rich cell-penetrating peptides

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    AbstractArginine-rich cell-penetrating peptides are short cationic peptides capable of traversing the plasma membranes of eukaryotic cells. While successful intracellular delivery of many biologically active macromolecules has been accomplished using these peptides, their mechanisms of cell entry are still under investigation. Recent dialogue has centered on a debate over the roles that direct translocation and endocytotic pathways play in internalization of cell-penetrating peptides. In this paper, we review the evidence for the broad range of proposed mechanisms, and show that each distinct process requires negative Gaussian membrane curvature as a necessary condition. Generation of negative Gaussian curvature by cell-penetrating peptides is directly related to their arginine content. We illustrate these concepts using HIV TAT as an example

    Study of the Anti-Proliferative Activity of 5-Substituted 4,7-Dimethoxy-1,3-Benzodioxole Derivatives of SY-1 from Antrodia camphorata on Human COLO 205 Colon Cancer Cells

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    A set of 10 4,7-dimethoxy-1,3-benzodioxole derivatives based on a lead compound previously discovered by our group, SY-1, which was isolated from Antrodia camphorata, were evaluated for their in vitro inhibitory activity on human colorectal carcinoma cells (COLO 205). Structure-activity relationship studies of the 10 compounds indicated the importance of the chain length of the alkyl group at the 5-position, and the 2-propenyl substituent named “apiole” exhibited the most potent inhibitory activity. In the present study, we demonstrate that the SY-1 analogue “apiole” decreased the proliferation of COLO 205 cells, but not that of normal human colonic epithelial cells (FHC). The G0/G1 cell cycle arrest induced by apiole (75–225 μM) was associated with significantly increased levels of p53, p21 and p27 and decreased levels of cyclin D1. Concerning COLO 205 cell apoptosis, apiole (>150 μM) treatment significantly increased the levels of cleaved caspases 3, 8, 9 and bax/bcl-2 ratio and induced ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. These findings suggest that apiole can suppress COLO 205 cell growth; however, the detailed mechanisms of these processes require further investigation

    Interaction of CO2 laser-modified nylon with osteoblast cells in relation to wettability

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    It has been amply demonstrated previously that CO2 lasers hold the ability to surface modify various polymers. In addition, it has been observed that these surface enhancements can augment the biomimetic nature of the laser irradiated materials. This research has employed a CO2 laser marker to produce trench and hatch topographical patterns with peak heights of around 1 ÎĽm on the surface of nylon 6,6. The patterns generated have been analysed using white light interferometery, optical microscopy and X-ray photoelectron spectroscopy was employed to determine the surface oxygen content. Contact angle measurements were used to characterize each sample in terms of wettability. Generally, it was seen that as a result of laser processing the contact angle, surface roughness and surface oxygen content increased whilst the apparent polar and total surface energies decreased. The increase in contact angle and reduction in surface energy components was found to be on account of a mixed intermediate state wetting regime owing to the change in roughness due to the induced topographical patterns. To determine the biomimetic nature of the modified and as-received control samples each one was seeded with 2Ă—104 cells/ml normal human osteoblast cells and observed after periods of 24 hours and 4 days using optical microscopy and SEM to determine mean cell cover densities and variations in cell morphology. In addition a haeymocytometer was used to show that the cell count for the laser patterned samples had increased by up to a factor of 1.5 compared to the as-received control sample after 4 days of incubation. Significantly, it was determined that all laser-induced patterns gave rise to better cell response in comparison to the as-received control sample studied due to increased preferential cell growth on those surfaces with increased surface roughness

    The contents and forms of solid-phase species of radioactive strontium and cesium in Taiwan soils

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    This study was to investigate the activities and contents of Cs-137 in the profiles of selected arable and forest soils in Taiwan and various solid-phase species of Sr-85 and Cs-137 in selected arable soils in Taiwan. The gamma (gamma) ray spectra of the collected soil samples and some of the soils amended with Sr-85 and Cs-137 were measured. The data indicate that the arable soils from Sanhsing series, Sanhsing Township and Chuangwei series, Chuangwei Township, Ilan County, and from Tunglochuan series, Pinglin Township, Taipei County shows significantly higher radioactivity of Cs-137 ( ND - 11.0 +/- 0.2 Bq kg(-1)). Furthermore, the radioactivity of Cs-137 in the mountain soils ( 1.24 +/- 0.07 - 42 +/- 1 Bq kg(-1)) from Yuanyang Lake Nature Preserve among Ilan, Taoyuan, and Hsinchu Counties is the highest among the investigated mountain forest soils. This may be mainly attributed to the fact that Ilan County is located in the northeastern part of Taiwan and faces the northeastern and northern seasonal winds with lots of precipitation annually from mid-autumn through mid-spring next year and is receiving greater amount of fallouts yearly. Due to longer reaction period (> 3 y) of Cs-137 with soil components, Cs-137 was mainly in the forms bound to oxides and to organic matter in the soil amended with Cs-137 and in the soil contaminated with Cs-137. On the contrary, due to shorter reaction period (< 60 d) of Sr-85 with soil components, Sr-85 was mainly in exchangeable form and partially in the forms bound to carbonates and oxides in the soils amended with Sr-85

    Energy Flow in Interjet Radiation

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    We study the distribution of transverse energy, Q_Omega, radiated into an arbitrary interjet angular region, Omega, in high-p_T two-jet events. Using an approximation that emphasizes radiation directly from the partons that undergo the hard scattering, we find a distribution that can be extrapolated smoothly to Q_Omega=Lambda_QCD, where it vanishes. This method, which we apply numerically in a valence quark approximation, provides a class of predictions on transverse energy radiated between jets, as a function of jet energy and rapidity, and of the choice of the region Omega in which the energy is measured. We discuss the relation of our approximation to the radiation from unobserved partons of intermediate energy, whose importance was identified by Dasgupta and Salam.Comment: 26 pages, 8 eps figures. Revised to include a discussion of non-global logarithm

    Theory and computation of covariant Lyapunov vectors

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    Lyapunov exponents are well-known characteristic numbers that describe growth rates of perturbations applied to a trajectory of a dynamical system in different state space directions. Covariant (or characteristic) Lyapunov vectors indicate these directions. Though the concept of these vectors has been known for a long time, they became practically computable only recently due to algorithms suggested by Ginelli et al. [Phys. Rev. Lett. 99, 2007, 130601] and by Wolfe and Samelson [Tellus 59A, 2007, 355]. In view of the great interest in covariant Lyapunov vectors and their wide range of potential applications, in this article we summarize the available information related to Lyapunov vectors and provide a detailed explanation of both the theoretical basics and numerical algorithms. We introduce the notion of adjoint covariant Lyapunov vectors. The angles between these vectors and the original covariant vectors are norm-independent and can be considered as characteristic numbers. Moreover, we present and study in detail an improved approach for computing covariant Lyapunov vectors. Also we describe, how one can test for hyperbolicity of chaotic dynamics without explicitly computing covariant vectors.Comment: 21 pages, 5 figure
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