Using Graph Parsing for Automatic Graph Drawing

: This paper presents a procedure for automatically drawing directed graphs. Our system, CG, uses a unique clan-based graph decomposition to determine intrinsic substructures (clans) in the graph and to produce a parse tree. The tree is given attributes that specify the node layout. CG then uses tree properties with the addition of "routing nodes" to route the edges. The objective of the system is to provide, automatically, an aesthetically pleasing visual layout for arbitrary directed graphs. The prototype has shown the strengths of this approach. The innovative strategy of clanbased graph decomposition is the first digraph drawing technique to analyze locality in the graph in two dimensions. The typical approach to drawing digraphs uses a single dimension, level, to arrange the nodes. 1. Introduction Directed graphs, or digraphs, are an excellent means of conveying the structure and operation of many types of systems. They are capable of representing not only the overall structure of..

An evolutionary approach to active suspension design of rail vehicles

This paper presents an application of a constrained multiobjective evolutionary algorithm for the design of active suspension controllers for light rail vehicles with the aim of providing superior ride comfort within the suspension's stroke limitation. A multibody dynamic model of a three-car train is derived and the control parameters are optimized. Force cancellation, skyhook damper, and track-following are used to synthesize the active controller. Selection of the active suspension parameters is aided by an evolutionary computation algorithm to get the best compromise between ride quality and suspension deflections due to irregular gradient tracks. An evolutionary multiobjective optimization approach accompanied with the Pareto set is proposed to deal with the complicated control design problem

A hybrid evolutionary approach for robust active suspension design of light rail vehicles

This paper is concerned with the design of a robust active suspension controller for light rail vehicles aimed at providing superior ride comfort within the suspension's traveling range. A multibody dynamic model of a three-car train is set up and the control parameters are optimized. Force cancellation, sky-hook damper, and track-following concepts are used to synthesize the active controller. Selection of the active suspension parameters is aided by an evolutionary computation algorithm to get the best compromise between ride quality, suspension deflections due to irregular gradient tracks, and robust stability of the control system. A mixed gradient and evolutionary multiobjective optimization approach accompanied with the Pareto set and variable weights are developed to deal with the complicated control design task. Extensive simulations and comparisons are performed to verify the proposed design

Influence of substitutions in asymmetric porphyrins on intracellular uptake, subcellular localization and phototoxicity in hela cells

The asymmetric porphyrins with different substituents show various bioactivities in biomedical application. In this study, a series of asymmetric porphyrins with varying proportion of substituents, such as hydroxyphenyl and aminophenyl, were synthesized and characterized to evaluate their cell uptake, intracellular localization, cytotoxicities and phototoxicities in vitro. Among these synthesized porphyrins, 5-(4-aminophenyl)-10,15,20-tri-(4-hydroxyphenyl)-21,23H-porphyrin (porphyrin 5), which was mainly localized in mitochondria and with high quantum yields of singlet oxygen, is a potential candidate for photodynamic therapy. The effective phototoxicity of porphyrin 5 is mainly due to the higher extent in the cells and the selective mitochondrialocalization. Comparing the partition coefficients of porphyrin derivatives, the best cellular uptake performs apparently with a partition coefficient (log p) ranging from about 1.7 to 1.9. In summary, higher quantum yields of singlet oxygen, and more specific mitochondrial localization of porphyrin 5 demonstrate its potential application in photodynamic therapy

Enhanced cytotoxicity of saporin by polyamidoamine dendrimer conjugation and photochemical internalization

Because of the lack of membrane binding subunit, type I ribosome-inactivating proteins (RIPs) are not very toxic to cells unless action is taken to allow for toxin internalization to the cytosol. To overcome the potential barriers that greatly hinder the cellular uptake and intracellular release of saporin, a type I RIP, we used generation 4 polyamidoamine (PAMAM) dendrimer as the carrier to improve its endocytic uptake, passive tumor targeting, and implemented the photochemical internalization (PCI) technology to facilitate its cytosolic release. Our results showed that the cellular uptake of saporin was increased after conjugation with the PAMAM dendrimer and the cytotoxic effect was improved by more than I order of magnitude. The cytotoxicity of free saporin and PAMAM-saporin was further enhanced by the PCI technology. PCI changed the mechanism of cellular uptake of free saporin and then caused more saporin entering into the cells. After the PCI treatment, PAMAM-saporin was not only internalized into the cytosol but also efficiently entered the nuclei. Our results indicated that conjugating to PAMAM dendrimer is a possible approach to enhance the cellular uptake of saporin. PCI is a promising technology to significantly enhance the cytotoxicity of both free saporin and PAMAM-saporin. Combining both polymer conjugation and PCI approaches may improve the efficacy of RIPs in cancer therapy. (C) 2007 Wiley Periodicals, Inc

Optimal design for passive suspension of a light rail vehicle using constrained multiobjective evolutionary search

This research proposes a systematic and effective optimization process for the design of vertical passive suspension of light rail vehicles (LRVs) using new constrained multiobjective evolution algorithms. A multibody dynamic model of the three-car train set is presented and the suspension spring and damping parameters are optimally designed. A new design of the passive suspension is aided by the use of evolution algorithms to attain the best compromise between ride quality and suspension deflections due to irregular gradient tracks. Extensive simulations are performed to verify the proposed design scheme. The preliminary results show that, when the passive suspension is optimized via the proposed approach, a substantial improvement in the vertical ride quality is obtained while keeping the suspension deflections within their allowable clearance when the light rail vehicle runs onto the worst track condition. (c) 2004 Elsevier Ltd. All rights reserved

Study on antioxidant activity of Echinacea purpurea L. extracts and its impact on cell viability

This study investigates the antioxidant activity of Echinacea Purpurea L. (EP) extracts and its impact on cell viability. The polysaccharides content of EP was 159.8 +/- 12.4 mg/g dry weight (DW), with extracts obtained by applying 55% ethanol at 55 degrees C containing 11.0 +/- 1.0 mg gallic acid equivalent/g DW of total phenolic compound. Trolox equivalent antioxidant capacity, 0.1 mg/mL of EP extracts exhibited only 30% when compared to the ascorbic acid at the same concentration. Reducing power of extracts increased linearly with its concentration and the concentration at 2.0 mg/mL reached about 65% of ascorbic acid at 0.3 mg/mL. The chelating capacity of ferrous iron (Fe(2+)) was 70% as good as that of the synthetic metal chelater EDTA when added to 5.0 mg/mL of EP extracts. The DPPH scavenging capacity showed 85.1% at 0.5 mg/mL of extracts and with half-effective doses (ED(50)) was measured at 0.23 mg/mL. The superoxide anions scavenging capacity of EP extracts was nearly equivalent to ascorbic acid (91.1% vs 93.0%) at the same concentration of 1.6 mg/mL and ED(50) was 0.32 and 0.13 mg/mL, respectively. Microculture tetrazolium assays showed extracts had 92% cell viability at 1.6 mg/mL for chicken's peripheral blood mononuclear cells (PBMCs) and 84% for RAW 264.7 macrophages, neither reaching the IC(50) level. In summary, the EP extracts had antioxidant activity similar to that of ascorbic acid, but have no serious effect on inhibiting chicken's PBMCs viability

Doxorubicin delivery by polyamidoamine dendrimer conjugation and photochemical internalization for cancer therapy

Coupling anticancer drugs to synthetic polymers is a promising approach to improve the efficacy and reduce the side effects of these drugs. The pH-activated polymer has been demonstrated to be a successful drug delivery vehicle system, whereas the photochemical internalization (PCI) was invented for site-specific delivery of membrane impermeable macromolecules from endocytic vesicles into the cyrosol. In this study, doxorubicin (DOX) was conjugated to polyamidoamine (PAMAM) dendrimers via pH-sensitive and -insensitive linkers and was combined with different PCI strategies to evaluate the cytotoxic effects. Our results showed that both PCI strategies significantly improved the cytotoxicity, of free DOX on Ca9-22 cells at higher concentrations. The 'light after' PCI treatment was efficient in releasing DOX from the PAMAM-hyd-DOX conjugates, resulted in more nuclear accumulation of DOX and more cell death through synergistic effects. On the other hand, antagonism was observed when 'light before' PCI combined with PAMAM-hyd-DOX conjugate. The distribution of PAMAM-amide-DOX was mainly cytosolic with or without PCI treatments. Both PCI strategies failed to improve the cytotoxicity of PAMAM-amide-DOX conjugates. Our results provide invaluable information in the future design of drug-polymer complexes for multi-modality cancer treatments. (c) 2007 Elsevier B.V. All rights reserved