Discovering frequent geometric subgraphs

Data mining-based analysis methods are increasingly being applied to data sets derived from science and engineering domains that model various physical phenomena and objects. In many of these data sets, a key requirement for their effective analysis is the ability to capture the relational and geometric characteristics of the underlying entities and objects. Geometric graphs, by modeling the various physical entities and their relationships with vertices and edges, provide a natural method to represent such data sets. In this paper we present gFSG, a computationally efficient algorithm for finding frequent patterns corresponding to geometric subgraphs in a large collection of geometric graphs. gFSG is able to discover geometric subgraphs that can be rotation, scaling, and translation invariant, and it can accommodate inherent errors on the coordinates of the vertices. We evaluated its performance using a large database of over 20,000 chemical structures, and our results show that it requires relatively little time, can accommodate low support values, and scales linearly with the number of transactions.     

Synthesis, characterization, and biological applications of multifluorescent silica nanoparticles

Multifluorescent silica nanoparticles were synthesized by the St?ber method using conjugates of (3-aminopropyl)triethoxysilane and fluorescent dye-N-hydroxysuccinimide esters. The nanoparticles containing the fluorescent dyes were well dispersed and showed high, stable, and tunable fluorescence intensities. In addition, we prepared multifluorescent silica nanoparticles containing two kinds of fluorescent dyes and used the nanoparticles in biological applications. Flow cytometry analysis showed high and tuned fluorescence and multiple fluorescences from single nanoparticles with diameters of approximately 400 nm. Fluorescence microscopy analysis also showed high and tuned fluorescence, as well as multiple fluorescences from single nanoparticles and from cells labeled with multifluorescent silica nanoparticles. The intracellular distribution of nanoparticles was evaluated by confocal microscopy and electron microscopy. We discuss the advantages and demonstrate the usefulness of our nanoparticles in relation to commercially available fluorescent nanoparticles including quantum dots.     

Near‐Infrared Fluorescent Silica/Porphyrin Hybrid Nanorings for In Vivo Cancer Imaging

Ring‐shaped silica nanoparticles are synthesized with a high tetrakis(4‐carboxyphenyl)porphyrin (TCPP) content or silica/TCPP hybrid nanorings (HNRs) using a one‐pot sol‐gel reaction with a TCPP‐binding silica precursor for fluorescence imaging of tumor. The shape of the HNRs is a reflection of abundant ring‐shaped TCPP aggregates in the silica matrix. The HNRs are of a size that makes them susceptible to the enhanced permeability and retention effect. For comparison, the TCPP‐doped silica nanoparticles are synthesized using a conventional method. The nanoparticles are spherical in shape because little TCPP is contained in the silica matrix and are designated as TCPP‐containing silica nanospheres (NSs). The absorption bands of the HNRs shift by about 20 nm toward longer wavelengths compared with the TCPP bands. This redshift leads the excitation wavelength of the HNRs into the near‐infrared (NIR) region. Therefore, the HNRs are excited by NIR light to emit strong fluorescence, although the NSs emit no fluorescence. The PEGylated HNRs (PEG‐HNRs) are uncharged and possess a significantly longer blood circulation time than PEG‐NSs. The PEG‐HNRs accumulate in tumor through multiple factors including their size, uncharged surface, unique shape, and long circulation time in blood, resulting in the acquisition of clear images of tumor.     

Conjugated linoleic acid modulates tissue levels of chemical mediators and immunoglobulins in rats

The effects of conjugated linoleic acid (CLA) on the levels of chemical mediators in peritoneal exudate cells, spleen and lung, and the concentration of immunoglobulins in mesenteric lymph node and splenic lymphocytes and in serum were examined in rats. After feeding diets containing either 0 (control), 0.5 or 1.0% CLA for 3 wk, there was a trend toward a reduction in the release of leukotriene B₄ (LTB₄) from the exudate cells in response to the dietary CLA levels. However, CLA did not appear to affect the release of histamine. A similar dose-response pattern also was observed in splenic LTB₄, lung LTC₄ and serum prostaglandin E₂ levels, and the differences in these indices between the control and 1.0% CLA groups were all statistically significant. The reduction by CLA of the proportions of n−6 polyunsaturated fatty acids in peritoneal exudate cells and splenic lymphocyte total lipids seems to be responsible at least in part for the reduced eicosanoid levels. Splenic levels of immunoglobulin A (IgA), IgG, and IgM increased while those of IgE decreased significantly in animals fed the 1.0% CLA diet. This was reflected in the serum levels of immunoglobulins. The levels of IgA, IgG, and IgM in mesenteric lymph node lymphocytes increased in a dose-dependent manner, while IgE was reduced in those fed the higher CLA intake. However, no differences were seen in the proportion of T-lymphocyte subsets of mesenteric lymph node. These results support the view that CLA mitigates the food-induced allergic reaction.     

Lymphatic transport of a physical mixture of medium-and long-chain TAG in rats

Lymphatic transport of a mixture of medium-chain TAG (MCT) and long-chain TAG (LCT) was studied in lymph-cannulated rats. Animals were administered a test emulsion containing either triolein, tricaprylin, or a 1∶1 mixture of triolein and tricaprylin, and the lymph was collected for 24 h. The lymphatic recovery rate of medium-chain FA (MCFA) was significantly higher in rats given the TAG mixture than in those given MCT alone. The lymphatic recovery rate of long-chain FA (LCFA) also was significantly higher in rats given the TAG mixture than in those given LCT alone. No TAG containing three MCFA (i.e., MCT) was detected, and 37.7% of TAG containing one or two MCFA was detected in the lymph TAG when rats were given the TAG mixture. These results indicate that lymphatic transport of MCFA and LCFA can be modified by the combination of MCT and LCT.     

NUMERICAL STUDY OF FLOW IN CONICAL DIFFUSER WITH VORTEX GENERATOR JETS

To develop vortex generator jet (VGJ) method for flow control, the turbulence flow in a 144°conical diffuser with and without vortex generator jets are simulated by solving Navier-Stokes equations with κ -ε turbulence model. The diffuser performance, based on different velocity ratio (ratio of the jet speed to the mainstream velocity), is investigated and compared with the experimental study. On the basis of the flow characteristics using computation fluid dynamics (CFD) method observed in the conical diffuser and the downstream development of the longitudinal vortices, attempt is made to correlate the pressure recovery coefficient with the behavior of vortices produced by vortex generator jets.